The French are selling up on Ailesbury Road, both the lavish residence and the nearby chancery steeped in rebel history, writes Property Editor Orna Mulcahy

At €60 million it is Ireland's most expensive house but then there aren't many private homes in Ballsbridge where you can comfortably seat 45 to dinner, or throw up a marquee for 1,000 in the back garden.

You can at 53 Ailesbury Road, the French embassy residence, which has come on the market through Lisney. By far the largest and grandest detached house in the city, it has been owned by the French since the 1920s. The French Government is also selling its chancery offices across the road at 36 Ailesbury Road, a house steeped in rebel history. IRA leader Ernie O'Malley was sprung from a secret room in the house in a gun battle in 1922 in which a Free State soldier was killed and O'Malley captured.

The house stands on an acre of ground backing onto Wanderers Rugby Club and is for sale at €20 million.

The French are selling up as part of a worldwide policy to downsize and modernise diplomatic properties. According to Lisney's John O'Sullivan, the plan is to purchase a new embassy and residence nearby. They may even consider exchanging the residence for an alternative house and cash. That kind of deal might appeal to wealthy property investors in the neighbourhood such as financier Derek Quinlan or property developers Sean Dunne and Bernard McNamara, who have lavish homes in D4.

The landmark house, dating from 1900, has over 1,022sq m (11,000sq ft) of living space, including a magnificent 40ft drawingroom with three fireplaces, a restaurant-sized kitchen, extensive staff quarters and a cellar - French vintages only of course. A grand staircase rises from the magnificent entrance hall, while the staff use a narrow back stairs from the basement to the top floor where one of the prettiest rooms in the house is a laundry.

The first floor has the private quarters of the ambassador, and a vast bedroom where Charles de Gaulle once rested on a visit to Ireland. Downstairs, the ambassador's study, lined in a stunning red toile, has a portrait of Sarkozy, though it's unlikely that he and his bride Carla Bruni will stay there before it is sold.

French ambassador, Yvon Roe D'Albert, who has been in residence for just six months, says that while the house is undoubtedly impressive for parties it is not entirely suitable for families. "It's so big, I have to call my wife on her mobile phone if I want to talk to her."

Ailesbury Road has plenty of impressive homes on its mile-long stretch but the French embassy is king of the road. With its 1.75 acres of garden, double entrance and stately portico, it's the ultimate townhouse, dreamed up by a rags to riches emigrant by the name of George Bustard. As a boy selling newspapers in Donnybrook Fair in the 1840s Bustard, so the story goes, found a wallet full of money and restored it to its owner. With the reward money he booked his passage to Australia where he made his fortune in construction.

He always planned to return to Donnybrook to build a mansion but he died in Australia, leaving his children to carry out his plans for the house, which he stipulated be called Mytilene. No expense was to be spared and the unusual white bricks cost a fortune in themselves.

Bustard said the home must house everyone, with separate suites for his son and three daughters as well as lavish reception rooms.

Complicated stairways and passages were needed to make this layout possible, and it was said that originally the house had 40 rooms. Eventually just two of Bustard's children lived there, elderly sisters who laid the table every night for all four siblings, another stipulation in their farther's will. In 1930 Mytilene was bought by the French Government and became the residence of the first Minister to France in Ireland. The name was erased from the pillars and the house is now simply known as number 53.

Across the road is 36 Ailesbury Road, the embassy offices, which are also for sale. Dating from 1920 it has a fascinating rebel history. It was built by the republican Batt O'Connor, a friend of Michael Collins, for a widow, Nell Humphreys, whose family were wealthy supporters of Irish independence. The two-storey redbrick was used as a safe house in the War of Independence, sheltering Irish fugitives. It was also the setting for cabinet meetings of the underground republican government. A secret room was built and in 1922 the house was raided by the Free State troops who sprung Ernie O'Malley from the secret room in a gun battle that left one soldier dead and O'Malley wounded.