Past Perfect - Irregular verbs

There is no simple rule for forming the past participle of irregular verbs. It is a good idea to learn the common past participles. You can find these in the verbs tables of dictionaries under past participle.
Use part of the verb avoir according to who or what did the action and add the past participle.
These are common irregular past participles with their meanings:

​j'ai
tu as
il a / on a
elle a
nous avons
vous avez
ils ont
elles ont

+

compris 
couru 
dit 
dû 
écrit 
fait 
lu 
mis 
pris 
pu 
reçu 
voulu 
vu

understood 
ran 
said 
had to 
wrote 
did / made 
read 
put 
took 
could / was able to 
received 
wanted 
saw

---