French city river, one end to the other (5)
I believe the answer is:
tours
'french city' is the definition.
(I've seen this in another clue)
'river one end to the other' is the wordplay.
I cannot really see how this works, but
'river' could be 'r' (abbreviation for river) and 'r' is found within the answer.
'one' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
The remaining letters 'us' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tours that I've seen before include "Travels round -- French 7" , "city in France" , "Martin's home" , "French town" , "Capital of France's Indre-et-Loire department" .)