I passed into a dim lobby, to be challenged by a sleepy voice behind a half open window.

The owner of the voice kept himself invisible and was no doubt in the bunk which he called his bed.

Only a stern sense of duty as concierge woke him up enough to demand, mechanically, who it was that the strange monsieur desired to visit at this late hour?
I replied according to instructions.

I wished to see Monsieur Gestre.
"Monsieur Gestre is away," murmured the voice behind the little window.
I thought quickly.

Gestre was probably the "pal" whom "J.M." had been in such a hurry to find.