Its distinctive yellow plasterwork is pockmarked, filthy and peeling. Trees and shrubs grow unchecked across the grounds, poking through windows, even sprouting from the four-storey roof.
Just across the street stands the imposing, buttery-gold post office, built in 1895 but now restored, in daily use, and commanding the centre of the old French quarter.
The two buildings show the contrasting fates that can await the colonial heritage buildings of Cambodia’s capital, built during the heyday of the French protectorate, but now often derelict and coming under economic pressure for the prime real estate they occupy.
Some can be restored to profitability as high-end venues, said Philippe Delanghe, a culture specialist in UNESCO’s culture unit.
He cited the Hotel le Royal, a favourite haunt of A-list visitors from its opening in 1929, and then of journalists covering the war in the 1970s, recently restored to its former glory by hotel operator Raffles into one of the city’s most desirable addresses.
Another success story is the Van restaurant near the river, built to house the Indochina Bank in the mid 19th Century, restored by the prosperous Van family a few years ago and now considered one of the best restaurants in town.
Beyond the hospitality sector, there is also a market for prestigious official property.
The old post office building now houses the Ministry of Posts and Telecommunications, while another French-built edifice has been repurposed as the British Ambassador’s residence.
And appropriately enough, the offices of the United Nation’s cultural arm UNESCO are in a pristine late 19th-century villa built in the Sino-Khmer colonial style, with a pillared, two-storey facade.
But the market is limited for such high-profile restorations, as the current owners of The Mansion are experiencing.
Built as the private residence of a wealthy Cambodian trader in French protectorate style between 1910 and 1920, The Mansion is struggling to find a buyer despite its prime location.
It was abandoned in the 1975 fall of Phnom Penh, then occupied between 1979 and 1989 by the Vietnamese army after the defeat of the Khmer Rouge.
The current owners, who run the Foreign Correspondents’ Club behind it, hold cultural events there, imbued with a sense of history by the once-golden walls now pockmarked by bullets, damp and mould.
The charm is not to all tastes. A “for sale” sign has hung on the outside wall for several months now, but real-estate firm CBRE has had few serious enquiries about the “unique colonial building.”
“A lot of people have been interested and we have had a few offers,” from both Cambodians and foreigners, but none for the 3.5-million-dollar asking price, she said.
“The price for the mansion is higher than the normal property but we can only market to a limited group of people,” said Thida Ann, an associate director at CBRE Cambodia.
If the cost proves too high, The Mansion may not be safe from the wrecking ball, despite its classified status with the Ministry of Land Management and Urban Planning.
In principle, a 1996 law says any building “proposed for classification or classified” may not be altered without authorization.
But in practice there is “nothing strictly enforced” when it comes to French heritage buildings, UNESCO’s Delanghe said. “There is no real preservation,” he told dpa.
Many potentially classifiable buildings have been demolished to develop the high-value land they occupied.
The distinctive Bridge Tower House, built as a French administration building in 1890, was razed in 2012 despite opposition from preservationists, including UNESCO.
A modern, colourful auto shop now sits in its place, to the consternation of activists who say the owner had committed to rebuilding in the same style.
“It’s not really expensive if you want to restore,” says Sylvain Ulisse, a project manager at the Heritage Mission, a joint awareness-raising initiative by the French embassy and the government.
“The main problem is that the cost of the land is so high that it’s really difficult to have the idea to renovate, because you think: ‘I can have a high building, and I will make more money on it.'”
“When they knock down and build high, there is more value,” said Sung Bonna, chief of the Bonna Realty Group, adding that he is personally in favour of restoration where possible.
“We need some funds to support or projects to buy those properties and renovate them and use them for tourism purpose.”
Heritage Mission’s Ulisse agrees, saying, “If we don’t do something now, we will lose a lot of these heritage buildings.”