The French made it known that if the RAAF used it's Mirages in Vietnam they would embargo the spares and support, much like what they did to Israel at about the same time. However Israel was and remains an international outcast, mainly to placate oil supplying and canal owning Arabs.
Australia on the other hand doesn't arouse nearly as much passion. So what would be the impact on the French if the RAAF used Mirages in Vietnam? Would Mirage and other military equipment sales dry up?