Area of Celtic ethnogenesis

[Tomenable]

I am reading a book by archaeologist A. Kokowski and there is an interesting map showing the area of Celtic ethnogenesis:
This area is "a - obszar genezy Celtów", as you can see much of Eastern France was also part of this area according to him:

https://i.postimg.cc/qpFvrG16/Celtic-ethnogenesis.png

 

[Maciamo]

It could be controversial to say that only Halstatt and La Tène were Celtic cultures. Most of Western Europe was already Celtic before that. Halstatt and La Tène are considered the Classical Celtic cultures. They help spread the Iron Age Celtic culture and P-Celtic languages (as opposed to the older Q-Celtic branch, which survived in Ireland and Scotland).