So, my advices:
Slide 1: I don't know if FreeNAS is the N°1 worldwide on the NAS market (maybe you wanted to say N°1 of the free NAS solutions, not all NAS solutions), you may want to check that if not already done.
Slide 2: "ne pas être dépendant d'un constructeur" and "pouvoir choisir le hardware librement" are basically the same thing, I guess you can regroup them into one item. One of the main advantage is missing: it uses ZFS which is a copy on write FS and a RAID controller at the same time which gives it a lot of advantages.
Slide 3: The slide is far too short on the history and inaccurate: FreeNAS and NAS4Free aren't two branches, they are forks; FreeNAS was a community maintained software based on FreeBSD and m0n0wall, in 2009 it has been decided FN needed to be rewritten and they switched to a Debian based system (which is now known as OpenMediaVault), then the FreeBSD based version FreeNAS 7 has been renamed to NAS4Free and is still maintained by the community, at the same time iXsystems rewrote FreeNAS using FreeBSD 8 and FreeNAS 8.x was born. Now it's still maintained by iXsystems and is actually at version 9.10 (using FreeBSD 10).
FreeNAS isn't the pro version and NAS4Free isn't the consumer version, they are basically for the same market but have some philosophical differences.
Slide 8: This slide doesn't focus on the main advantages of ZFS IMHO: the 16 EiB limit is a good idea to mention but for the others items: ZFS uses checksums on all the data so what's read is guaranteed to be what's was wrote (but needs ECC RAM to do it properly), it can do snapshots of the data, it can easily replicate the snapshots to another server for backup purpose, it handles compression, deduplication and encryption (NB: encryption is best translated by chiffrement, not by cryptage), it self heals and has some of the most reliable RAID modes actually availables, it can use almost all of the RAM as very efficient cache (called ARC) and it can scale up to thousands of drives arrays.
Slide 9: Strippe is spelled Stripe. Maybe mention N drives mirrors.
Slide 11: maybe talk about vdevs and pools before talking about datasets and zvols. You can use this diagram if you want
https://forums.freenas.org/index.php?threads/comprehensive-diagram-of-the-zfs-structure.38865/
Slide 13: sharing protocoles and OS pairs are inaccurate: UNIX systems can mount SMB or NFS (and maybe even AFP) not just NFS for example.