  We introduce a concentration property for probability measures on
$\scriptstyle{R^n}$, which we call Property~($\scriptstyle\tau$); we show that
this property has an interesting stability under products and contractions
(Lemmas 1,~2,~3). Using property~($\scriptstyle\tau$), we give a short proof
for a recent deviation inequality due to Talagrand. In a third section, we also
recover known concentration results for Gaussian measures using our approach.}
