Last night I watched a talk show on TV5Monde (Mots croises), all participants (including representatives of the government, small businesses, UMP, PS, and CGT) concurred - didn't object that the french work less per week than others. Besides the info presented by Jerome, and the OECD data discussed by HugoMe and Laurent, here is what I found at Eurostat:

Mean number of hours worked per week in 2006 according to Eurostat.

Definition: Average number of usual weekly hours of work in main job, full-time/part-time. It includes all hours including extra hours, either paid or unpaid, but excludes the travel time between home and the place of work as well as the main meal breaks (normally taken at midday). Persons who have also worked at home are asked to include the number of hours they have worked at home. Apprentices, trainees and other persons in vocational training are asked to exclude the time spent in school or other special training centres

UK: 36.9
Danemark: 35.3
France: 38.1
Germany (2005): 35.7
Italy: 38.6
Netherland: 30.9
Sweden: 36.4

Most other EU countries since 1991 listed here: Hours of work per week Eurostat data set

So what gives? Is there something we don't know about Eurostat data? Why are the CGT and the PS drinking the Kool-Aid on this?