"l'a défini" and "la définit"

Question

How do I distinguish between "l'a défini" and "la définit" from speech? Are there any clues to point at the tense used?

Cécile Janty-Davies · Accepted Answer

Hi Boticelli, 
Good question! Normally, I would say context but it doesn't really work here.
The difference is between 
La constitution qui la définit = The constitution which defines it 
and 
La constitution qui l'a définie = The constitution which has defined it 
Having said this, as the text is in the present tense it is correct to say 'qui la définit' in the present tense.
I have always wondered why we are still in the Cinquième  République , I have never known (consciously)  any other as it dates back from 1958 but I asked a French lawyer this very question and she answered me that it needs a change in the constitution which hasn't happened since De Gaulle made some important changes at that time.
You might be interested in finding out about those on the following page -
https://www.conseil-constitutionnel.fr/la-constitution/que-change-le-regime-de-la-veme-republique-institue-par-la-constitution-du-4-octobre-1958-par
Bonne Continuation!