And, you're wrong to claim it is an attack on freedom of religion. Freedom of religion means freedom to practice, worship, express one's religion, and that's still granted. That freedom doesn't mean freedom of religion to turn neutral, secular environments like state schools into environments where religion becomes a factor of separation and conflict.
It's a basic matter of relations between state and church, where both have their own separate environments, and have to keep out of each other's business. The state won't tell religious leaders what to preach in their churches, synagogues or mosques - the church, synagogues and mosques won't demand their views and practiced be endorsed in the state's own premises, where it is the state, not religion, which sets the rules.
Freedom of religion cannot mean making demands to change principles of education like equality between genders and equality between all religions. Everybody has to accept those principles, if they send their kids to a state school. They can't demand their young girls be exempted from a class because their religion prevents them from taking that class. They are free to have their kids pursue education elsewhere where those special exemptions are granted, if it is allowed, but they can't demand they be tolerated and endorsed in schools that must remain a neutral ground for all.
At least, that's how I see it. The Islamic fundamentalists are typcally using this issue as an ideological battle tool, and in complete disregard of the actual wishes of the more secular-minded Muslims in France.
It is puzzling that some libertarians end up siding with the fundamentalists rather than the Muslims who accept and respect secular principles.