I do not speak French, but that doesn’t matter. I know what I am seeing here.
Warning: not suitable for children
Since I originally posted this, some eagle-eyed people suggested this may be faked – the UN letters seem to disappear off the car near the end of the video. That was also my initially reaction after being told this and watching it again, so I took down the post.
But I believe it may really be a UN car after all, with the lighting making it look like the letters disappeared as the car moves down the road.
Here is a frame from the video. Note the black marks on the top and side.

I have also marked the number plate. Note how it looks white, as compared to the yellow number plate on the car to the left.
UN cars in Israel have white number plates.
In other words, I believe this is really a case of putting the united into United Nations.
If so, I very much doubt they would have pulled this stunt in Gaza.
Hat tip: Michal