French: teaches about pawn chains and proper wing attacks. Both players often attack on the root of pawn chain and mobilize the pieces on the side with space advantage. Black often has space advantage on queen side, white has on king side. Black often attacks on white's d4 square for example Nb8-Nc6, Ng8-Ne7-Nf5, Qd8-Qb6, Bc8-Bg4 (to trade bishop to Nf3 that defends d4 pawn).
Source: Here.
