Derek Quinlan, Ireland's best-known international property developer, is set to lose many tens of millions of euro on a €65m mansion he bought and refurbished at the height of the property boom over four years ago. Quinlan has formally put the south of France property on sale for €80m but local estimates say it is worth closer to €40m.

The Sunday Tribune has learned that the sale of Villa Carriere and its 8,000 sq m seafront parklands on Cap Ferrat, the exclusive Cote d'Azur retreat of the world's super rich and Russian oligarchs, comes as the Monaco branch of Barclays Bank indicated it would consider court proceedings over the mortgages secured on the property.

Barclays Bank in London refused to comment.

The formal sale may indicate that Quinlan, who left the Cap Ferrat property over a year ago to live in Epalinges, a Swiss town near Lausanne, is concluding talks with creditors.

Sources on Cap Ferrat said La Carriere was officially on the market for €80m but that Quinlan and the bank "would be lucky" to get €40m because the Cote d'Azur property market was in crisis.