  It has recently been proved that the class of unital exact C*-algebras is
closed under taking reduced amalgamated free products. In particular, this
implied that the class of exact discrete groups is closed under taking
amalgamated free products. Here a proof is presented of a special case: that
the class of exact discrete groups is closed under taking free products (with
amalgamation over the identity element). The proof of this special case is
considerably simpler than in full generality.
