Guy on the water in France a fine hat (7)
I believe the answer is:
chapeau
'a fine hat' is the definition.
'chapeau' can be an answer for 'hat' (synonyms). I'm unsure of the 'a fine' bit.
'guy on the water in france' is the wordplay.
'guy' becomes 'chap' (both can mean a man).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'the water in france' becomes 'eau' ('water' in French).
'chap'+'eau'='CHAPEAU'
Can you help me to learn more?
(Other definitions for chapeau that I've seen before include "Cap (French or heraldic?)" , "something to put on noodles" , "(French) hat" , "Fashionable hat" .)