The coffins were to be loaded onto a plane following a ceremony at a military airport in Kabul attended by the French ambassador Bernard Bajolet.
President Nicolas Sarkozy will lead a ceremony of remembrance for the soldiers in Paris on Tuesday.
The seven soldiers were killed in three separate incidents over four days in Kapisa province, around 60 kilometres (40 miles) northeast of Kabul.
Five died along with an Afghan civilian in a suicide attack on Wednesday, the worst loss of life for French forces since August 2008, when 10 soldiers were killed in a Taliban ambush east of Kabul.
Around 4,000 French troops are serving in Afghanistan, most in Kapisa, and Sarkozy has said all will be withdrawn by 2014.