This is a map of Paris metro area. BTW don't pay any attention to the names of the towns written on it, people who edited that map may have needed to point out those particular ones but they're insignificant to us here :
So that's one of metropolitan France's 22 regions (the whole country including overseas territories has 27), called Ile-de-France and divided as any French region into numbered administrative entities called départements. As shown on the map above, Ile-de-France is made of 8 départements :
Paris (75)
Seine-et-Marne (77)
Yvelines (78)
Essonne (91)
Hauts-de-Seine (92)
Seine-Saint-Denis (93)
Val-de-Marne (94)
Val-d'Oise (95)
Asnières-sur-Seine (or simply Asnières) featured in this thread is located in Hauts-de-Seine, one of the 3 inner, smaller départements adjacent to Paris. Those 3 are quite densely populated, they're actually nearly as dense as Paris itself. I think the main thing to keep them apart from the center is the périphérique boulevard surrounding Paris. That so-called boulevard is actually a damn freeway, an unfortunate barrier unfriendly as it can be from my point of view. Of course it's a symbolic frontier; as soon as you cross it to get out of the center, housing prices tend to decrease although they remain very high in the wealthiest suburban towns, especially in Hauts-de-Seine. But in Seine-Saint-Denis in particular, prices dramatically decrease since that département is still regarded the poorest and roughest of the region.
The 4 outer départements are totally different. That's where you want to live if you like the suburbia lifestyle : your single family home with a yard and that kind of stuff, which has some good points too.
For some historic reasons, Paris (75), Hauts-de-Seine (92) and Yvelines (78) are the wealthiest and best developed départements, you can enjoy a high standard of living in many places of those 3, at least if you've got enough money. They're the oldest developed areas. Large developments in the rest of the region started much later, I guess that's why they generally don't feel as pleasant.
The whole region count roughly 12 million inhabitants. Voilà, as always Wikipedia's your friend if you're curious and want some further info.