I live in France where tap water is considered good and very tightly controlled.

You cannot go wrong with tap water.

Now, there is the matter of taste. My tap water is ok, some are much better. I drink from a Brita pitcher (the one with overpriced filters) and the taste is noticeably better.

But again it is just the taste. The safety of tap water is a given here (town halls have to post results from water tests that are done on a regular basis).