Frenchman landing place with royal backing (6)
I believe the answer is:
pierre
'frenchman' is the definition.
(I've seen this before)
'landing place with royal backing' is the wordplay.
'landing place' becomes 'pier' (pier is a kind of landing place).
'with' means one lot of letters go next to another.
'royal' becomes 'er' (I've seen this in other clues).
'backing' says the letters should be written backwards.
'er' in reverse letter order is 're'.
'pier'+'re'='PIERRE'
(Other definitions for pierre that I've seen before include "French first name" , "French boy's name" , "Peter, to the French" , "One colouring cloth" , "See 17" .)