Translation:The Italian is selling wine to the Frenchman.
"French" can be used as a noun to denote the people of France or the French language (see http://www.thefreedictionary.com/french), but I'm not sure whether it can be used in the meaning "a (single!) person from France, Frenchman"... Hence I would translate "Włoch sprzedaje wino Francuzowi" = "The Italian sells wine to the Frenchman" (one French person) and "The Italian sells wine to the French" = "Włoch sprzedaje wino Francuzom" (many French people).
Correct. It can refer collectively to all people of France, but not to an individual. Based on the hover hints, I assumed this sentence was talking about French wine, not selling wine to a French person... I have reported it.
Some strange answers have been accepted here... fixed now, "a French" won't work anymore.
Actually, this sounds strangely bad, even though I know it's correct and there's nothing wrong with it.
I got it wrong (not a rare event), but how would I say the Italian is selling French wine?