I just attended a seminar regarding Asiatic Hornet, very interesting and very worrying.
Apparently the first nest in France was near Sarlat in about 2004 (accidentally of deliberately the jury's still out). They have been gradually spreading north-westwards and were last year in Creuse and up as far as Nantes.
They are about the same size as a wasp and they are the only Frelon in France which is black and yellow as opposed to brown. It also has distinctive yellow legs.
The queen is prolific and also lays more queen eggs so they can dissipate more quickly. Nests can be anywhere from ground level to 30m (100ft) above the ground.
The biggest cause for concern is that they kill honey bees and can take over their hives. Hives can be protected with a metal strip with holes no more than 5mm diameter (Asiatic Frelon's limit is 7mm).
Link attached explains more, http://zebulon1er.free.fr/Frelon.htm