Wednesdays are funny in France. It's like a parenthetical notation in the sentence that is the rest of the week. Grade school children don't have school so you see them everywhere. Either with their mothers or grandparents or caregivers or in groups with adults from childcare centers being led around the city center. To the library, to the cinema, to the shops, to the bakery.
If someone mentions work schedules and says quatre/cinquième (4/5), chances are the one day off is wednesday. When a mother says she's returning to work, after a parental leave, for example, the first question everyone will ask her is: As-tu ton mercredi? Do you have your wednesday (off)? All the sports activites and music classes and pony clubs and whatever else are on wednesdays, which means most moms spend the day in the car.
I don't know quite how I feel about it. I like having a break in my work week, it's a day to catch up on papers I need to grade or lessons to plan. And it's nice for the kids to have a break too, their school days are really long, especially on the two days when they eat at the cafeteria. 8:30-4:30. That's 8 hours. It's organized well, recess happens twice in the morning and twice in the afternoon, but still. I sometimes wonder if they wouldn't do better in a system that had fewer hours everyday, including wednesday. It's been talked about occasionally here. But then everyone who has a job linked to the current schedule throws a fit. The teachers because they like the break to do the same things as me. The sports and activites people because they like to be able to do things all the same day. And then of course everyone starts tossing out the French classic: mais ça a toujours été comme ça. But it's always been that way.