At the beginning of the 20th century, the master of St. Petersburg Art Nouveau, Roman Fyodorovich Meltzer, decided to build his own house on Kamenny Island. From 1901, the architect's project was repeatedly changed, and in 1904 it was finalized.

The Meltzer mansion, which can be seen from the embankment of Krestovka, is one of the key monuments of northern Art Nouveau in St. Petersburg. When constructing the mansion, Meltzer used motifs of ancient Russian architecture and Russian national architecture. Undoubtedly, elements of Finnish national romanticism played a significant role in the appearance of the house.

The house’s picturesque character is given by walls made of roughly hewn stone, massive logs, and a high pyramidal roof. The most attention is attracted by the gable roof, which becomes the defining part of the silhouette and soars upward.

The three-story, rectangular-in-plan building with a high gable roof is located in the center of the plot. The lower floor of the house is made of light limestone and red facing brick, the upper one - of logs. No facade of the house repeats another. Among the greenery of the trees, the building has a fairy-tale appearance, which is why St. Petersburg residents have long nicknamed it the "Baba Yaga House" or the "Fairy Tale House."

In the center of the first floor was a hall with a fireplace and a staircase leading to the second and third floors. The first floor also housed a vestibule, kitchen, bathroom, and living room. On the second floor were Meltzer's office and workshop, as well as a library, dining room, and some other rooms. In the wooden part of the house, the rooms remained unplastered, which was meant to evoke a rural dwelling.

Low partitions, combined furniture, and built-in equipment divided the interior space of the house. The tiled stoves were faced with green and blue tiles from the Finnish factory "Abo." The furniture was made according to Meltzer's drawings at the "F. Meltzer & Co." furniture factory, owned by the architect's father (R. F. Meltzer was a co-owner and artistic director of the factory). 

In 1907, a service wing was built on the opposite side of Polevaya Alley (house 6) according to Meltzer’s project. This plot was purchased by Meltzer from Countess Kleinmichel.

During the division of property in 1916, the mansion passed to the architect’s brother, F. F. Meltzer. In 1918, the house was handed over to a children’s labor colony. At the end of the 1920s, the mansion’s premises were converted into communal housing.

In the early 1970s, after reconstruction and remodeling, the house became a state dacha of the Main Directorate of Internal Affairs of Leningrad and the region.

In the 1990s, an international detective story began around the building. 

In 1991, Franz Sedelmayer arrived in Leningrad as a German security consultant to engage in family business in Russia: it was reported that his father supplied special equipment for the German army and police. According to some sources, Sedelmayer Jr.'s plans included "equipping Russian police officers—from shoelaces to special vehicles, training special unit personnel," as well as creating a private security company in Russia. The name Sedelmayer—the owner of the company Sedelmayer Group of Companies International Inc. (SGC International), registered in St. Louis, Missouri, USA—first appeared in the Russian press in 1992. The article spoke about the intention of JSC "Kamenny Island" (KOC)—a joint venture established by the St. Petersburg Main Directorate of Internal Affairs and Sedelmayer’s company (each co-founder owned 50% of the shares)—to supply imported special equipment both for the police and for commercial enterprises and private individuals. The city police contributed to the joint venture with 20,000 square meters of land and the right to a 25-year lease of the mansion of architect Meltzer, located at Polevaya Alley, house 6. The German entrepreneur, in turn, paid for the building’s renovation, spending two million dollars on it (according to other sources, one and a half million dollars).

It was noted that at that time, after Anatoly Sobchak was elected mayor of St. Petersburg, the post of chairman of the Mayor’s Committee for External Relations, responsible for international relations and foreign investments, was held by Vladimir Putin. Later, Sedelmayer himself stated that Putin visited him at Kamenny Island. According to the entrepreneur, they were connected by joint work on organizing the special unit "GRAD" in St. Petersburg, created in anticipation of the 1994 Goodwill Games.

In 1993, KOC became one of the founders of the Regional Fund for the Security of Entrepreneurship and Individuals. However, soon the Main Directorate of Internal Affairs ceased to participate in the project, withdrawing from the joint venture because state organizations were prohibited from engaging in commercial activities. "Kamenny Island" continued to use the building; soon the joint venture was re-registered and became a private security company "established by individuals with foreign capital participation."

In 1995, the economic administration of the Russian President Boris Yeltsin decided to place the presidential residence in the mansion leased by Sedelmayer. According to Sueddeutsche Zeitung, Sedelmayer was informed about the contract cancellation by phone by Putin, as he was responsible in the mayor’s office for contacts with foreign businessmen. According to Kommersant, the security company was first asked to vacate the building and then find new premises. There was no talk of compensating "Kamenny Island" for the renovation and reconstruction costs, so the security company employees refused to leave under such conditions. Herman Gref, who worked in the Committee for City Property Management of St. Petersburg, told the press that "Kamenny Island" did not provide documents that could confirm the amount of expenses for the building’s reconstruction. According to some sources, Sedelmayer refused the property offered to him in exchange for the mansion on Kamenny Island.

Even after KOC ceased to exist, Sedelmayer refused to vacate the premises and even entered into confrontation with the police. It was noted that Sedelmayer’s own security service held a siege for three months, but after that, the inventory in the house was confiscated, and the house itself was sealed according to Presidential Order No. 633-pp. Sedelmayer himself had to leave Russia for personal reasons but was not allowed to return—he was denied entry to the country. In 1996, the mansion was transferred to the disposal of the Administrative Department of the President of the Russian Federation, then headed by Pavel Borodin. Later, this federal residence became known as "K-4."

Sedelmayer filed a lawsuit against Russia at the Arbitration Institute of the Stockholm Chamber of Commerce. In 1996 (according to other sources—in July 1998), the court satisfied the businessman’s claims, deciding to recover from the Russian Federation in favor of Franz Sedelmayer compensation in the amount of 2.5 million dollars. Based on this verdict, the Higher Regional Court of Berlin issued an enforcement order. Despite this, Russia did not recognize the International Arbitration decision, citing that the mansion and land during the specified period were not city but federal property, and therefore the Leningrad City Executive Committee had no right to dispose of them.

In 2001, the Berlin Court of Appeal issued a ruling according to which Sedelmayer could seize any Russian property on the territory of the Federal Republic of Germany.

The businessman tried to use this opportunity to seize Russian property. Sedelmayer succeeded only in February 2006. According to several media reports, the court transferred under his control the building of the former residential complex of the Russian trade mission in Cologne, located at Friedrich-Engels-Straße, 7. It was reported that it was previously used by the KGB of the USSR, and by that time immigrants from Russia lived there. At that time, the approximate value of the building, according to the press, was 40 million dollars, while Russia’s debts to Sedelmayer, which had grown over several years due to interest, amounted to about 5 million dollars. At that time, it was suggested that Sedelmayer would now manage the rent payments for the building.

According to other sources, initially, to pay off the debt to Sedelmayer, the court decided to sell not the building but the entire complex of trade mission buildings with a total area of about 15,000 square meters. But this real estate object was never sold because Russia appealed the court decision in higher instances. In October 2006, the court in Frankfurt am Main issued a decision to seize rental payments received by Ost-West Handelsbank (formerly the Soviet foreign bank). At the same time, Sedelmayer did not receive compensation from the rental payments because, after the Cologne court decision appeared, Russia transferred the buildings to the use of a state unitary enterprise, which could not act as a defendant for state debts (moreover, it, in turn, leased the building to the German company Fa. GAG Immobilien AG). As a result, in May 2007, Russia managed to obtain the cancellation of the foreclosure decision on the property in the Cologne court of first instance.

In March 2008, the Higher Court of the state of North Rhine-Westphalia in Cologne ruled that Russia remained the owner of this property and ordered the sale at auction of the former Soviet trade mission complex to repay the Russian debt to Sedelmayer (including interest, it had already reached 4.9 million euros). The court decision stipulated that the seizure could not be imposed on rental income.

In February 2014, Sedelmayer succeeded in selling the property of the Russian trade mission in Cologne at auction for 5 million euros (6.5 million dollars). According to Sedelmayer, 3.2 million euros were transferred to the court account, but he had not yet received this money, and one of the plots worth 1.8 million euros was not paid for, so it would be put up for sale again.

In September 2009, Sedelmayer tried to sue Russia for the building of the Russian Science and Culture Center ("Russian House") on Friedrichstraße in Berlin. This building was managed by Rossotrudnichestvo; its total value was estimated at 116 million euros. On September 9, 2009, the district court of Berlin’s Mitte district ordered the confiscation of the "Russian House" and its transfer to a temporary administrator, who was to collect rent from leased premises (including a jewelry store on the first floor) and, prospectively, put the "Russian House" up for auction to pay off the debt to Sedelmayer. However, at the end of the month, the same district court recognized that the building was used for the sovereign purposes of the Russian Federation and canceled its confiscation order.

After the failure with the "Russian House," Sedelmayer attempted to sue for Russian property in Sweden. In October 2010, he told the press that the Stockholm City Court, at his suit, imposed a general seizure on Russian state property in Sweden, and that bailiffs had already seized some buildings belonging to Russian state bodies and enterprises. According to him, the court compiled a list of objects that could be confiscated, and "a conservative estimate of Russian state property in Sweden is at least 2-3 million euros." It later became clear that this was a six-story building of the Russian trade mission on the island of Lidingö near Stockholm. According to Sedelmayer, it was rented out as offices, but the Presidential Administrative Department of the Russian Federation stated that it was not used for commercial purposes. Despite the Russian side’s protest, the court upheld the seizure of the property. In early July 2011, the Supreme Court of Sweden confirmed the right to seize and subsequently auction off the premises of the trade mission’s residential building. The Administrative Department considered this decision "illegitimate and unenforceable." The building with the plot was sold on the third attempt in September 2014 for 1.68 million dollars, which Russia appealed. As of 2015, the legal battles continue.

On November 12, 2010, the Stockholm City Court made another ruling in favor of Sedelmayer, fining the Russian state-owned company Russwood AB 107 thousand dollars.

In September 2011, it became known that Sedelmayer had succeeded in seizing 138 thousand euros deposited by the Russian authorities in the Stockholm Chamber of Commerce to cover Russia’s expenses for arbitration proceedings in Sweden.

Sources:

https://www.citywalls.ru/house13782.html

https://ru.wikipedia.org/wiki/Усадьба_Мельцера