Appears in collection : Algèbre, Géométrie et Physique : une conférence en l'honneur

We shall explain how using a motivic Poisson formula due to Hrushovskiand Kazhdan, it is possible to prove for equivariant compactifications of additive groups a geometric version of a conjecture of Manin on asymptotics of the number of points of bounded height. This is joint work with A. Chambert-Loir.