Alexander Sergeievich Stroganov.

[nevsky 17]

a)Sergei Vasilievitch Saltykov (Paul’s father), who "was ambassador to Paris 1761-1762" (History of My Life By Giacomo Casanova, Willard R. Trask, p356) married 1750 to a “Matryona Pavlovna”.. ….
b) Peter Semen Saltycov, governor of Moscau (with whom Catherine corresponded in French).

1.Casanova's "Matryona Pavlovna" translates as "Pavel's mother".
2. Peter Semenovich Soltikow's role and "french" identity can be traced at http://ebooks.adelaide.edu.au/c/chesterfield/letters/volume8.html (and volume 9, re Peter I's disposal)

[nevsky 17]

Correction of previous post : "Peter I" should read "Peter III".

Furthermore (re count Stroganov):

June 9, 1762 Count Stroganov who was in attendance behind her chair at a gala dinner to celebrate the peace treaty with Prussia, supports Catherine who is insulted by Peter III (Catherine the Great, by Virginia Rounding, p 138)

(Peter III was deposed on July 9, 1762, when Catherine "fled" from suburban Peterhof to St. Petersburg to be proclaimed empress by the Guards and the Senate.)