TITLE: Who is M. Meyniel?
QUESTION [10 upvotes]: Does anyone know anything about M. Meyniel? According to zbMath, he published precisely one mathematics paper, in which he gave a sufficient condition for hamiltonicity of digraphs:

"Une condition suffisante d'existence d'un circuit hamiltonien dans un graphe oriente" (JCTB 14 (1973), 137–147).

In that paper, he was listed with an address but no affiliation. The address was 13, rue Poirier de Narçay, Paris 14ᵉ, which appears to be an apartment above a game store for what it is worth.
I assume that M. Meyniel is distinct from Henri Meyniel of Meyniel graphs and Meyniel's conjecture. That said, the paper "Sufficient conditions for a digraph to be Hamiltonian" (J. Graph Th. 22 (1996) 181–187) is dedicated to the memory of Henri Meyniel and lists Henri Meyniel as the author of M. Meyniel's paper (item [15] in the bibliography).

REPLY [22 votes]: You can be quite sure that M. Meyniel means "Monsieur Meyniel" (a common usage in French).
Here is what I think is definite proof that M. Meyniel is H. Meyniel: The acknowledgement of the 1973 paper by M. Meyniel thanks J.C. Bermond, so evidently Bermond knew the author. In the article Cycles in digraphs - a survey Bermond and Thomassen cite the 1973 paper as follows:

Meyniel, H., Une condition suffisante d'existance d'un circuit hamiltonien dans un graphe orienté, J. Combinatorial Theory B 14(1937), 137–147