You can pronounce it however you want.
If you want to respect the French origin, it's "de broy", like "boy", and a very short "uh" as the vowel of the "de".
https://www.princeton.edu/~achaney/tmve/wiki100k/docs/Louis_de_Broglie.html
If you click the hyperlinked IPA in that article, it goes to the wikipedia page for IPA.
We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.