No one cares about Ligue 1, so, obviously, that is a lot of undiscovered players here. And Sanson is definitely one of these.
With 2209 in game stats it's obviously that he has at least some potential. But I tell you that he's already a good option for a Ligue 1 or a French squad. With no poor stats in any position, you'll not need big improvements, so you can choose the chemistry style like your preferences. Shadow if he gonna be a CDM, Hunter if you already have one or two defensive midfielders or Architect, if you like a very solid box-to-box.
The truth is: he already can compete with Pogba (compare, trust me) and, scoring goal each week like he does, it's just a time question before he can get an IF and become a beast for just 40k!
I have 1 million in cash and can't find a better player to make my 3 players line (4-3-2-1) with Bakayoko and Tolisso OTW.
So, for conclusion, he is a complete player. Very decent in each part of the field. With a +3 upgrade, he'll definitely become a beast.
Very decente stats in every category
Nice weak foot
Very nice long shots (despite 72)
69 balance could disturb a little bit