How to pronounce the names of composers

[(poco) Sforzando]

Not really.  It depends if the last letter of the word is pronounced or not.  For Schubert it is not.  So both syllables have the same intensity and are pronnouced chou-bair.
For Schonberg, the G is pronounced.  This puts a stress on the last syllable as you say..

But you will agree that neither composer's name is pronounced by the French as it should properly be in German, with stress on the first syllable?

And while I don't want to go through the film again just to check the pronunciation of one name, my distinct impression was that Huppert said choo-BAIR and not choo-bair.

[(poco) Sforzando]

Hah, I know what you mean. In French swearing, they always seem to say "merde" with an emphasis on the "de" -- "mer-duh". The more exasperated they are, the longer the emphasis on the "de" becomes.

In 2007 I stayed with a French family for the Summer (part of an immersion program) and they had a dog (named Rena). One time the dog threw up in the house. I was in the other room, but I distinctly remember hearing my host mom yelling at the dog:

"Rena! Non! Rena!! RENA!! NON!!!"

*sound of dog throwing up*

"mer-duuuuuuuhhh!"

They may have elongated the DUUUUUUHH, but they did not stress the second syllable.

Similarly, when I studied French in school, I was told that in a word like trente-trois, the second "e" is always silent. Not so when I heard native a Frenchmen speak the word slowly. But he wasn't throwing up, and Spineur can verify oui ou non here.

[Visions_fugitives]

Pronunciation, according to Wikipedia: [dy fa(j)i]

It's great to always learn new things.
I always called him Dufé.
That must be why he never answered

[Visions_fugitives]

Regarding Beethoven, here in Italy you will almost always hear " Be-TO-ven".
But you would also hear "Shu-MA-ker", among others, so it is no surprise.

[Jo498]

To my recollection, the name Beethoven is also wrongly stressed in the song "Roll over BeetHOVen"

[zamyrabyrd]

It's funny to hear in Israel (where they could have gotten it right) like on the radio or wherever, "Lee-o-nard" Bernstein, instead of "Lennard".

[zamyrabyrd]

Similarly, when I studied French in school, I was told that in a word like trente-trois, the second "e" is always silent. Not so when I heard native a Frenchmen speak the word slowly.

I always found a gap between what teachers say and what is done in the real world. And that goes for music, too.

[Ghost Sonata]

It's great to always learn new things.
I always called him Dufé.
That must be why he never answered