if you are uncomfortable playing against it play rubinstien

Speaking as a someone who plays the white side of the tarrasch ( so far only in lots of online blitz games) I always feel a little uneasy after 3..Nf6. I know that if I make a slight misstep or forget some of the theory, then I can be blown away - if  black knows his stuff.

Provided your comfortable with sharp and tactical play, I always believe in going for these types of sharp positions as black (if possible) in whatever opening you choose. To prove that I practice what I preach, I play the hyper - accelerated dragon as black - with lots of success.

For most amateurs ( like myself ) it is hard to learn all the theory you need to know as white in the all the many different openings. This means that as black you can often make lots of hay with these types of sharp lines - provided you've done some homework. It easy to see at white has difficulty in attempting to master a mainline repetoire. Consider for example Kalifman's series of books based on Anand's openings as white - there are going to be seven now I believe. Compare this to his book for the black openings according to  Karpov. It is half the size of his volume on the Mainlines of the Ruy alone. 

The other thing 3...Nf6 has going for it is that the types of positions tend to be pretty unique to this line of the Tarrash - I believe. Contrast that with the other lines - the IQP or the Qd5 lines, where the pawn structure at least are pretty familiar to most players.

For inspiration look at some of Ulhmans games in his famous book - I think Batsford published under the title 
"Winning with the French" - if you haven't read it already. My recollection is that at least at some point in his career he played this for a while - with some real nice games. Perhaps looking at these old games you'll gain a little more comfort and confidence in blacks position.

So in summary I would play 3..Nf6 - if I played the French.

I used to have the same problems against the Tarrasch. I consider 3...Nf6 to be slightly suspect. 3...Nc6 might be worth a shot now and then, but I`m not willing to study the resulting positions. I now play 3...Be7, which I am quite satisfied with. Works better than any other attempts I have tried against the Tarrasch. Try it.

In MnBs line : b) 12.Bf4 Bxf4 13.Nxf4  Ne4 white main options ( in short)are b1) 14 Ne2 Rxf3 b2) 14 g3 Qf6  Both very sharp positions ensues with black getting good play in my opinion

The last alternative is  b3) 14 Qc1 !? Ng4 15 Nxg4 Qxg4 16 Bxh7+ Kxh7 17 Nxe6 Qf6 18 Nxf8+ Qxf8 19 Qg5 Bf5

This last line is not entirely forced i guess, but white seem  to be slightly better in this position based on 2p +rook vrs B+N with king exposed. This seem to be a very tiresome postion to defend. Maybe 13... Ng4 is better?

After 1.e4 e6 2.d4 d5 3.Nd2 Nf6 4.e5 Nfd7 (alas Ne4 is too risky) 5.c3 (according to GM Van der Wiel more precise than 5.Bd3 b6!?) c5 6.Bd3 Nc6 7.Nge2 cxd4 8.cxd4 f6 9.exf6 Nxf6 10.Nf3 what is the difference between Qc7 11.o-o Bd6 and Bd6 11.o-o Qc7 ?
It is exactly because of the idea to exchange queens with Qg6+ - it happens in several forms - that I prefer to leave the queen on d8 for a while. So 10...Bd6 11.o-o o-o
a)12.Nc3 a6 13.Bg5 Qc7 and now 14.Bh4 Nh5 15.Qc2?! is met by Rxf3!
b)12.Bf4 Bxf4 13.Nxf4 and I have not decided yet between Ne4 and Ng4.
c)12.Bg5 and is e5!? playable? Or is Bd7 better? What about Qb6 ?

Greetings from Moengo, Suriname. Brugui: greet Rijkaard for me.

Normally the reason why you quit from a line is a mix of different things.... but ALWAYS there is a common pattern: yes, a defeat that you adjudicate to the opening.

Normally if you have some experience, a single game is not going to make you change... but a string of poor results are, definitly are.

I agree that giving a thougth to my desire to change and my worries about tarrasch could help me to understand my own game or style...

Well, I don't know others but in my case I started playing the French thinking on the Winawer or MAc. NEver thinking on facing the Tarrasch.

Then, I don't know about 3...Be7. It seems to me that I can give it a try... or two. Then possibly I will re-consider the matter.

Greetings from Barcelona

Nf6!   
Seems interesting  to know EXACTLY why somebody has trouble with some lines ?  Is it a matter of taste (eg "I prefer to play Black with an isolated pawn thus c5 is good" or "I prefer closed center thus Nf6 is good"...) or a matter of knowledge (eg "what line to play vs the universal system?") or choice (eg "I prefer Be7 because there exists few theortical published  lines")...

I too had trouble with 3....Nf6. Positions resulting from 3...Be7 is not to my liking. Toying with the idea of 5...Nc3 Guimard. For the time being parked myself with Fort Knox!