Where does “ヴィエンヌ” come from?

ヴィエンヌ (Japanese) comes from French Vienne, from Latin Vindobona, from Gaulish *Windobona.

Ancestry of “ヴィエンヌ”, step by step

Step	Language	Word	Meaning
1	French	Vienne	Vienna
2	Latin	Vindobona	—
3	Gaulish	*Windobona	—

ヴィエンヌ — Etymology, Origin & Word History | Etymology Explorer