The largest march occurred in Paris, with two to three thousand people attending.
It comes two days before a parliamentary vote on the positioning of France's troops in Afghanistan.
Germany protests
More than 5,000 people also took part in protests in the German cities of Berlin and Stuttgart, demanding that troops be brought home from the central Asian nation.
About 250 pacifist groups and trade union organisations had organised the demonstrations.
About 3,300 people marched in Berlin and another 2,000 in Stuttgart, although the organisers said a total of 7,000 people had took part.
'Give peace a chance'
Demonstrators carried banners with slogans including "Give peace a chance - Bring the troops back from Afghanistan."
Jens-Peter Steffen, who helped organise the Berlin rally, said: "There's another strategy for peace in Afghanistan that doesn't involve a military, and that strategy needs to be employed."
The German parliament is also going to a vote on October 7 on whether to send additional troops to Afghanistan.
France has more than 3,000 troops in Afghanistan with the 70,000 capita Nato-led force there. Germany has about 3,500 soldiers in the country.
Germany has lost about 30 German troops in Afghanistan since 2002 and France a total of 24 soldiers in the country.