Thank you for raising this, Luc. I came looking through the forums for advice on this variation because I am also seeing it a lot at my level (1400-1500 rapid on chess.com). Nc3 from White as early as move 4, after the exchange on d5, is by far the most common continuation I am facing, and I do think it is an omission that it is not even briefly touched upon in the course. 

1. e4, e6
2. d4, d5
3. exd5, exd5
4. Nc3…

The problem is that this seems to throw a spanner in the works immediately and makes it difficult for us to reach our desired setup. Since Bd6 is not an option now, Bb4 seems the best square for our dark squared Bishop. Be7 feels passive and doesn't allow us to play Nge7. 

However, the move Bb4 has three major drawbacks I have found. Firstly, the b4 square is no longer available to our c6 Knight, so we cannot play Nb4 in response to opponent's Bd3. This makes White's development very easy for them. Secondly, our control over e5 is weakened and White can maybe exploit this by sticking a Knight there later on. Finally, we are in danger of losing the Bishop after White kicks it with a3, forcing the exchange and giving White the Bishop pair advantage. Moreover, White doesn't have to rush the move a3 out. For instance, they can wait until it looks like we're committing to castling long, then play a3 and open up the b file for an attack.

For example:

4. Nc3, Nc6

5. Nf3, Bb4

6. Bd3…

…and we cannot play Nb4 as we might have liked to attack the Bishop on d3…

6. … Nge7

7. 0-0, Bg4

8. h3, Bf5

9. Bxf5, Nxf5

10. Re1+ …

…now look what happens if we continue as per the course recommended moves …

10. Re1+, Nce7

11. Qe2, Qd7

12. Ne5 …

Ouch! We are already paying for not having control of e5.

Ok, so what if we don't play Bf5, but go with something like Bh5 instead?

8. h3, Bh5

9. a3, Bxc3

10. bxc3, Qd7

11. a4, 0-0-0

12. Re1, f6

13. Ba3…

It is difficult to see a good plan for Black here, whereas White has the Bishop pair, the semi-open b file, and is having all the fun. Engine analysis suggests our best move is something prophylactic like a6 (to deny b5 from the Bishop). If we play the more aggressive g5 now, continuing with the plan suggested in the course, then White has a range of good options to punish us like a5, Bb5 or even the tactical shot Ne5! 

I've done quite a bit of analysis on this and I think White has the favourable position. Furthermore, I don't think it is the case that they have to play particularly well to get there. These are fairly logical moves for the most part that intermediate rated players can find.

So, what to do about Nc3? 

I honestly don't know. I've looked at playing Be7 and going for a different setup with short castling, but it feels boring and passive. The best I can come up with at the moment is to get to this kind of position and make sure I remember not to try something like g4 prematurely, but rather play defensive and solid for a few moves, and keep an eye on the b5 square for White's Bishop. It's not like we're losing. It's just that I would prefer White's position.

Does anyone have any thoughts or alternative ideas?

i rekomen you to play afer e4 e6 d4 d5 ed5 ed5 nc3 c6 and the new plan bd6 nf6 (if you got chek ne7) 0:0 bf5 ngd7 re8 ne4 ndf6 and rewaly akive poitzion and hard to play for white

Hi Luc and Jules… Hapy New Year to you!

Luc, don't be so pessimistic! 😅 We would never recommend a line in the French that must be abandoned on the move 5! 😄

This is a first practical repertoire and as such we cannot include all the replies to every move, that's why there is a forum and webinars and streams too.😃 
We do not recommend the move move 4...Bd6 for Black because it reduces somehow our possibilities, we will not be able to develop the bishop to b4 in some variations as in this case.

Therefore against 5.Nc3 we should go Bb4 pinning the knight. This will allow our knight to go to e7 and follow more or less our usual plan.💪