  We describe the conjugacy classes of affine automorphisms in the group
$Aut(n,\K)$ (respectively $Bir(\K^n)$) of automorphisms (respectively of
birational maps) of $\K^n$. From this we deduce also the classification of
conjugacy classes of automorphisms of $\Pn$ in the Cremona group $Bir(\K^n)$.
