When you move to Versailles and you know nobody in here, there will be no nice neighbors coming to wish you a warm welcome, carrying a bunch of freshly baked croissants, nor any invite to their apéro dinatoire (= drinks and nibbles informal sort of party, mostly an appetizer before the actual dinner) and there's even a smaller chance of someone insisting for you to come to their birthday party, even if you happen to share a wall and you are mutually acquainted with some private aspects of each other's lives.
All in all, you're on your own, my friend, and, unless you already are a superstar, you'll probably get royally ignored! You're gonna have to put in some effort (and frustration!) if you are eager to integrate, as the French are extremely family centered and they wouldn't risk their secure universe for anything in the world, not even for your overly smiling, nice self!
In these circumstances, two main solutions are presenting to you: