  We establish a new version of Floer homology for monotone Lagrangian
submanifolds and apply it to prove the following (generalized) version of
Audin's conjecture : if $L$ is an aspherical manifold which admits a monotone
Lagrangian embedding in ${\bf C^{n}}$, then its Maslov number equals $2$. We
also prove other results on the topology of monotone Lagrangian submanifolds
$L\subset M$ of maximal Maslov number under the hypothesis that they are
displaceable through a Hamiltonian isotopy.
