  Green and Ruzsa recently proved that for any $s\ge2$, any small squaring set
$A$ in a (multiplicative) abelian group, i.e. $|A\cdot A|<K|A|$, has a Freiman
$s$-model: it means that there exists a group $G$ and a Freiman $s$-isomorphism
from $A$ into $G$ such that $|G|<f(s,K)|A|$.
  In an unpublished note, Green proved that such a result does not necessarily
hold in non abelian groups if $s\ge64$. The aim of this paper is improve
Green's result by showing that it remains true under the weaker assumption
$s\ge6$.
