I know this is the Daily Mail but I am assuming they've got the facts straight.
"The increased levy on income from rented property and capital gains tax on sale profits could cost second-home owners thousands of pounds more a year....
The new property charges will apply to all home owners - foreigners and French expats - who live abroad and do not pay their taxes in France.
From July 1, they will be liable for a 15.5 per cent tax on income from renting their property, and 15.5 per cent on any profits made from selling it."
I should have questioned the accuracy. The Daily Mail says 'liable for a 15.5% tax' - the Telegraph adds the 15.5% onto the existing tax. Big difference!
"On Wednesday (July 4th), the French government announced it was to increase taxes on foreign-owned second homes. Tax on rental income would rise from 20 per cent to 35.5 per cent, and capital gains tax on property sales would rise from 19 per cent to 34.5 per cent. The extra in each case is being labelled a "social charge"."