congrats with everything!
However, I also think you should keep the apartment, and I'll supply with some experience of my own:
You say you're pregnant, which is wonderful (it will be somewhat relevant later).
When I was a baby, my parents owned a *huge* apartment in a nice part of the capital in addition to their house here (which we from now on can refer to redneckland). Anyways, they aren't really big fans of the capital, so they decided to sell this wonderful apartment, and at the time they sold it, the marked was terrible, so they sold it for a little bit more than $100 000 (though, it's almost 20 years ago, so it would probably be a bit more in today's currency), so they did not do it for the money. Anyways, they sold the apartment, and i grew up to hate redneckland but love the capital. However, it's far away, so everytime I went there and still do, I have to arrange with friends or fix an expensive hotel room everytime I go there, which is a lot of stress.
This year I'm moving to the capital from Redneckland and I've decided that I really want to live in the part of town where they had the apartment, but of course, the prices are crazy now, so I'll be lucky if I get an apartment to the fraction of the size and quality of the one my parents sold for twice the price they sold it for.. If my parents had kept the apartment instead of selling it years ago on the other hand, I'd have a huge apartment for free, and they would also have made money leasing it out throughout all these years I've been to school in Redneckland.
My parents knows that I'm PO'ed at them because they sold the apartment and now they will have to help me finance an apartment that's crappy in compair, so although *you* don't want to keep the apartment, think 20 years ahead in time - your child might love it and I doubt the prices on real estate will go down in Paris, so I guess you'll earn a bit if you put it up for lease..
Just my $.02