The present participles and past participles of verbs are often used as adjectives.
So they agree in number (singular/plural) and gender (feminine/masculine) with the noun they modify, just like regular adjectives.
The distinction between adjectives derived from present and past participles is similar to that between -ing and -ed adjectives in English: fatigant (tiring) / fatigué (tired).
The present participle is formed by dropping the -ons ending from the nous form in the present tense and adding -ant.
Past participle formation depends on the verb class (-er, -ir, -re, or irregular).
Note that past participles used as adjectives may have a passive meaning, and thus be followed by an agent introduced by par (by) or de (with):