Celebration in France is held by motor-racing authority (6)
I believe the answer is:
fiesta
'celebration' is the definition.
(fiesta is a kind of celebration)
'by motor-racing authority' is the wordplay.
'by' means one lot of letters go next to another.
'motor racing' becomes 'fi' (FI resembles Fe, Formula e).
'authority' becomes 'esta' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'fi' next to 'esta' is 'FIESTA'.
'in france is held' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for fiesta that I've seen before include "public event abroad" , "(Spanish) religious festival" , "A Spanish public celebration" , "Holiday; carnival" , "Latin American celebration" .)