Criteria criteria = session.createCriteria(Affaire.class);
if (auteur.getNom() != null && auteur.getNom().length > 0) {
  Criteria manyToMany = criteria.createCriteria("auteurs");
   manyToMany.add(Expression.like("nom","%" +   
  auteur.getNom() " +"%")
}
......
if (distrcit.getLibelleFr() != null && distrcit.getLibelleFr().length > 0) {
  Criteria manyToMany = criteria.createCriteria("communes");
  Criteria distrcitCriteria = manyToMany.createCriteria("district")
  distrcitCriteria .add(Expression.like("libelleFr","%" +
  district.getLibelleFr() " +"%")
}

  }