If he is French from France, and not Canadian (as in this case, it could be other reasons I guess), it's likely he gave this name because of the connotations of the name "Germaine".
Germaine is a very old-fashioned name. It's a given name. A granny name.
(Until it comes back à la mode again)
There's a Renaud's song (maybe he is a Renaud fan?) called "Germaine",
in which he declares his love to a woman called Germaine, that plays musette, and talks like Arletty. = It's not exactly an evidence of modernity. Hence the humorous side of the song, with a lag between his love as still a young man, and having a granny dancing the java.
The male name is Germain, and the female Germaine.
It's the equivalent of the name "Jermaine" in English (one of the brother of Michael Jackson), but given to girls.
The French name Germain became Jermaine in English, when borrowed.
Germaine could come from "Germany" (or rather "germanicus", from Germany) as one of the possible etymology, etc, but it's only the etymology, and only one of the hypothesis.
A more accepted one, is that "Germain" (male) "Germaine" (female) comes from the old German "gari", meaning "spear", and for the "main", the hypothesis are very different according to the source, some says it means "man", some other it's from "mundo" meaning "protective", so a protective spear...
Another possible etymology, is that it comes from the Latin "germanus" meanins "coming from the same blood/family".
The English word "germane" meaning related, comes from French "germain" as in "cousins germains".
I've searched for a possible link between the name "Germaine" and the prostitution (as you mentioned an "hotel"), and I've found nothing. So, it's not the right track.
It sounds more like a joke, rather than some other deep meanings.