My understanding is that "l'intelligence" can be a collective noun with the exact meaning you want. If the context makes that seem ambiguous, I'd say "les intellectuels", or even "l'élite intellectuelle".
If you want to be pejorative (and I suspect the origins of the word in Russian meant it probably was used as such more often than not), you could throw in the adjective "soi-disant"...!
We either use the word «intelligentsia» itself as it comes from Latin, so readily accepted, or if you absolutely want to use French words «l'élite intellectuelle» is accepted.
Intelligentsia (feminine noun) is as common a word in French as it is in English. You could also simply speak of les intellectuels (feminine intellectuelles), slang les intellos.
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