We find an expression for the joint Laplace transform of the law of (T [x,+∞[ , XT [x,+∞[ ) for a Lévy process X, where T [x,+∞[ is the first hitting time of [x, +∞[ by X. When X is an α-stable Lévy process, with 1 < α < 2, we show how to recover from this formula the law of XT [x,+∞[ ; this result was already obtained by D. Ray, in the symmetric case and by N. Bingham, in the case when X is non spectrally negative. Then, we study the behaviour of the time of first passage T [x,+∞[ conditioned to {XT [x,+∞[ − x ≤ h} when h tends to 0. This study brings forward an asymptotic variable T 0 x , which seems to be related to the absolute continuity of the law of the supremum of X.