As far as I remember, there is an enrollment bonus of 3000 points if you fly on AF within the first six months (or is it three?) of enrollment. In addition, there is currently a 10000 miles bonus for intercontinental flights via Paris (until end of June, I think).

On Pedro's question, the answer is that if your departure point is within Europe (and you are not a French resident), you only pay for the costliest of the segments (i.e. Lisbon-Glasgow = Lisbon-Paris = 25K (eco)/40K(biz.)