I go to the gym and kick box with guys but I know there is support in the UK among some women (Muslim and non-Muslim) for women only places at certain times or for certain events. I don't see why this can't include shopping days but I don't know if this idea of Women only times is accepted in French culture.
If it is already part of French culture, then as the store-owner admitted - his wording was clumsy - there was a probably a more acceptable way of putting his message across that would have fitted in with French cultural norms.
