My first reaction before doing preliminary research was “two topics this should be easy.” My current reaction is “there’s so little written about either of these that writing a paper entirely on them would be near impossible.” Yea.
However the internet is not a terrible place, fortunately. I was able to find a website with the complete programs for all the concerts La Societe des Concerts ever performed, and a slightly helpful history of the society. That and the Wikipedia page for the venue they performed in is really all I can find at the moment. Going through the BNF Gallica is a scary thing, and I have yet to find a primary source about my topics that are actually useful and supportive of any argument.
I’m hoping to prove that as a composer, my piece would or would not be played by the Society in their hall by analyzing the new music they perform, quotations by the director of the 20s. For me, finding accessible material and things that will point towards the point I will inevitably be making will be hard, seeing as there already is little material written about this society and concert hall.
I think it would be best seeing myself as a composer of the 20s seeing if my piece will be premiered by them. It would be difficult to make up a composer so I would have to pick a non-established composer of the era, as I think a well-established one would be taken in regardless.
Those are my fears, I’m sure they will grow and subside, and will be added to and subtracted from. Most rely on the ability to find sources that have significant enough content.
Research is hard! (Tell me about it.) But you’re on the right track. Remember that just knowing the programming of the société is huge – you can do lots of original analysis of programming trends, and argue that your composer would be likely or unlikely to break into their concerts. Also remember that you’ll likely find references to your institution in lots and lots of sources that focus on other things (composers, conductors, performers, nationalism, politics, other institutions) so you have to cast your net broadly. Targeted searches for “Société des Concerts” won’t do the trick, but looking through the indexes of 20 books on topics relating to 1920s Paris will. :)
Gentle reminder: This is the internet. If you mention a source that is accessible via the internet, you are almost required to hyperlink to it. Your website with complete concert listings? Yes, please, do share. Wikipedia? Sure, why not – although this seems like a great opportunity to warn future researchers against trusting a Wikipedia page based on an almost complete lack of scholary evidence.