France on Tuesday condemned the life sentence handed by a Turkish court to leading civil society activist Osman Kavala, saying his detention violated Turkey's international obligations.

"France strongly condemns the life sentence," the foreign ministry said, calling for Kavala's "immediate release" and the dropping of all charges against him.

He had been detained for more than four-and a-half years "in violation of Turkey's international obligations," the French ministry added.

France's statement echoes similar statements by Germany and the United States expressing dismay at the verdict issued by the Istanbul court.

The European Court of Human Rights (ECHR) had in December 2019 ordered Turkey to release Kavala, but he has always remained behind bars.

In February, the committee of ministers of the Council of Europe (COE), of which the ECHR is part, launched infringement proceedings against Turkey for only the second time in its history.

The proceedings could see Turkey suspended or in the most severe sanction even expelled from the COE. ECHR are rulings are binding for all COE member states.

The Istanbul court sentenced Kavala to life in prison on charges of trying to topple the government that have been rubbished by his supporters. It also jailed seven other defendants for 18 years each.