(bel air ) how did this name arrived?

Answer 1

"Bel-Air is a station of the Paris Métro, named after the Rue Dugommier. The station is located in the Boulevard de Picpus, between the districts of Picpus and Bel-Air.
The station is in the OPEN AIR (capitals added) at ground level, but the lines are underground to the north and to the south: the trains ascend to the surface before the station to descend when leaving it. "

It's French and in English it means "beautiful air."