But I also wonder why there's so many pharmacies in France. In almost any city I've been to it's hard to not have a green flashing cross in sight.

French pharmacies cannot open where they want, there is a limit in how many pharmacy a city can have, on the flip coin, it means that they are relatively evenly spread out across the country, and that even in the so called empty diagonal you`ll find a pharmacy.

Physician do not have this restriction, so many of them go to either Paris or the French riviera, while in rural area in the Northern half, you struggle to find a doctor.