Decision altitude for an a license is 2500 feet. Hell, most DZ's consider it pulling high if you're over 4000 ft, and require you to exit the plane last, if there are no wing suitters.

Reserved parachutes are TSO'd to open in 300 ft and are generally seven cells rather than the standard 9 cells for main canopies.

One of the jump requirements for your a license is to do a hop n pop (where you jump and deploy immediately) at 3500 to simulate an emergency.

Now, I don't know about France as different countries have different rules, but in America you have to be buckled in with the door closed until 1000 ft.

Source: got my a license last year, have fifty jumps, and have jumped out of a jet (a DC-9), and a Huey.

If the plane is having issues under a 1000 ft, it's going to be hard to get unbuckled, get the door open, and jump out. And even If the reserve is supposed to be fully open in 300 ft, I wouldn't want to jump anything below 1500, and that only of I was certain the plane was going down and I'd be stable on exit.