The court in Nantes upheld nine cases against which the defence ministry had lodged an appeal and found in three cases that their claim should proceed.
The claimants served in Algeria and the South Pacific between 1960 and 1996 when France tested its nuclear weapons.
Their lawyer said this marked an important decision but regretted that in the process, seven years had been lost.
France adopted a law in 2010 recognising that its tests were harmful but the compensation criteria were narrowly crafted that practically all claims were thrown out.
