Simcard for Belgium and France
 

Is there a prepaid sim card I can get in France that will work in France as well as in Belgium(atleast text or data)?

Any SIM card will work, but you'll be paying roaming charges to use a French SIM card in Belgium.

Best to buy two SIM cards.
We are different countries and no European SIM card exists. Now the roaming charges are being lowered (done or soon) but still.

I think the lowering of the roaming charges is happening in a few months' time, not sure when.

There are multi-country SIM cards, but they are a rip-off, at least the ones I've seen.

Roaming charges drop in April and are scrapped in June 2017. Not all payg plans allow you to load extra money on them when roaming. Some don't allow roaming at all.
Two Sims will almost certainly work out cheaper.