In theory, it is 7 hours a day (for 35 hours a week contracts). In reality, most office workers are pulling unpaid extra hours.

It's also possible to get 38.5 or 40 hours contracts, where you would get extra holidays to compensate (over a year).

I've worked as a programmer in France, Canada and England. In my experience France and England are pretty much the same in terms of work-time (8 hours/day, 5 week holiday), Canada is behind by lack of holiday (8 hours/day, generally 3 weeks holiday)

Edit: bare in mind this is based on my experience and will presumably be very different depending on the employer.