To indicate number with fingers in France I have read a couple variations.
Number 1. Just use your thumb. Numer 2. Thumb and Index.
Number 2. Just the Index. Which is it? What about 3 etc? There a site that lists there?
Use your thumb for 1, thumb and index for 2, thumb, index and middle for 3, etc. If you use just your index finger meaning 1 (like we do in the US) you may get 2. Hope this helps.