What shape is a French omelette and how is it achieved?
There isn't a standardised shape as such, but the rugby ball shape is common. To achieve this shape, all you have to do is cook your omelette (French style uses a super-hot pan and lots of butter), then roll three quarters of it up in the pan. 

Then nudge the omelette up the side of the pan a little, so that it partly protrudes over the edge, which will then allow you to flip the remaining quarter back over onto the rest of the omelette. You should now have a rugby ball shape with a 'seam', i.e. the edge of the omelette - simply turn this out so the 'seam' is on the plate and you have a nice smooth omelette showing on top.