The phone rings a lot at Paris Region Entreprises, a one-stop shop for companies deciding whether to move employees to the City of Light. Typically, callers ask about visas and minutiae of employment law. But not long ago, an executive from Japan called with a stumper: Where, he asked, are the dancing clubs? “It was a certain kind of club that nobody here had ever heard of,” said Robin Rivaton, the organization’s chief executive. “Kind of a social club for executives and their wives.