On the correlation of binary sequences

C. Mauduit conjectured that C2(E)CN3(EN) ?? Nc always holds with some constant 1/2< c = 1. This will be proved for c=2/3, more exactly if for a sequence EN =C {-1,+1}N we have C2 (EN) << N2/3 then  C3 (EN) ??  N1/2. Indeed, a more general theorem is proved, involving correlation measures.