Move 6)...Na5 fails to exploit a trap white has fallen into ; 6)...Nxe5 wins a pawn (white bishop is hanging and must trade, knight recaptures) and since the french holds long term positional play over tactics this pawn probaly means victory in end game.
6)...Na5 also drags your knight from the center and complicates getting the queen to b6, a square it needs to be on, after the bishop trade
Here's a recent live game 30 I played on chess.com. I'm new to the French, and this is the most solid I've played it so far, but I know I've missed some great tactics and positional considerations, so any help or advice would be much appreciated. Also, I know some of the endgame moves are especially suspect, as both myself and my opponent were nearing the end of our clocks, so if you have any good rules of thumb, feel free to relate them.