The present participle is formed from the first person plural of the present indicative. The ending is dropped, and to this stem is added the participle ending -ant:
chantons –-> chantant
parlons –-> parlant
Three participles are irregular:
avoir –-> ayant
être –-> étant
savoir –-> sachant
A. The present participle can be used as an adjective (many adjectives are actually based on present participles):
C'est un livre intéressant. (That's an interesting book.)
B. The present participle can be used to indicate a state of being or an action contemporaneous with the main verb:
Me croyant perdu, j'ai abandonné tout espoir. (Thinking myself lost, I gave up all hope.)
C. The participles for avoir and être can be used with past participles:
Ayant dépensé tout son argent, il est rentré. (Having spent all his money, he returned home.)
S'étant dit qu'elle serait trop en retard, elle a accéléré. (Having told herself that she would be too late, she accelerated.)
D. The present participle can be used with the preposition en to indicate a causal action or one of simultaneity with the main verb:
En parlant au téléphone, elle a fait un dessin. (While speaking on the phone, she doodled.)
En appelant la police tu m'as sauvé la vie! (By calling the police you saved my life!)