>He is also committed to correcting some of the outright lies often repeated, examples include: the Rebbe having studied at the Sorbonne
I haven’t read Deutsch’s book, but he would have to prove that Lubavitchers forged the Rebbe’s handwriting in two different places in the Sorbonne registration book in 1937 & 1938.
Highly unlikely.
Google “in the halls of the Sorbonne”
Minute 4:00 of the video