The new task force aims to "shed light on cultural assets of dubious origin held by public institutions", stolen between 1933 and 1945, the culture ministry said in a statement.

Around 2,000 artefacts sent from Germany to France after the war are held in French museums under special status as their owners have not been identified.

Their status also means they should never leave the country.

Researchers will work alongside museums, libraries, archives and the Foreign office to "examine cases one by one, whether they are filed by victims' families or uncovered by the investigation", the statement said.

France and Germany signed an agreement last month to improve cooperation on returning seized objects to their rightful owners.

The move comes after Prime Minister Edouard Philippe pledged during last year's commemorations of the Vel d'Hiv round-up of Jews in 1942 that the culture ministry would take "a much more active role in restitution work".

The government wants to ramp up efforts to return stolen works after it returned "several dozen" artefacts "over many years", it said.

"This is our duty to the victims of plundering," France's Culture Minister Franck Riester said. "It's about memory and justice".

In Austria, thousands of artworks stolen by the Nazis have been returned -- including major works worth millions of euros -- since a law was passed in 1998.