for context: https://youtu.be/fD-R35DSSZY?t=928 this is where I've seen the claim.
I've personally struggled to find any sources on Caesars senatorial appointments on the internet.
After some more searching, I was able to find an answer to my question myself. this comment by Celebreth has a quote from Suetonius' The Twelve Caesars LXVI (76) which is as follows:
With the same disregard of law and precedent he named magistrates for several years to come, bestowed the emblems of consular rank on ten ex-praetors, and admitted to the House men who had been given citizenship, and in some cases half-civilised Gauls.