Ok. I looked up my own question. In 1942 the Americans and the British landed in Morocco and Algeria under the code name 'Operation Torch'. The Allies were actually fired upon by the Vichy French, and the Allies retaliated. So, in a way, the British were 'at war' with the French in 1942.
Kromovaracum, French military personnel who decided to fight with the Allies were members of the Free French Forces, and not the Vichy French. Although the latter may have turned their allegiance AFTER the liberation of France.
I don't think there's been any fighting since Waterloo, unless you count fighting against some French in the Second World War while aiding others; so yes, I think so.
Shadow Man
Apart from Agincourt, the 100 Years War, the Twenty Years War, The Seven Years War, Waterloo, Trafalgar, Quebec & The Spanish Succession you are correct