I've seen my fair share of Asterix animations when I was younger, but I don't remember many specifics. It could very well be that I saw this film before, but it's a bit too generic to tell. If you need an introduction into the world of Asterix it's probably a decent starting point, but as a film it's just poor.
The story is extremely basic and taken directly from one of the comics. Asterix and Obelix get mixed up in an argument between Caesar and Cleopatra. They end up helping one of Cleopatra's architects to build her newest palace in record time. There's even some time for a couple of random musical bits in between, just to get to an acceptable runtime.
The animation is very limited (the camera for example is either complete static, panning or zooming, that is it), the character designs are typical but lack detail. It all comes off rather lazy and cheap, like a quick cash-in built on top of the success of the comics. It worked of course, but I felt this film wasn't worth revisiting.