This applies to several adjectives. If they stand before a noun that begins with a vowel or a silent h, they have a slightly different form.
| masculine | masculine before a vowel | feminine |
| beau | bel | belle |
| nouveau | nouvel | nouvelle |
| fou | fol | folle |
| mou | mol | molle |
| jumeau | jumel | jumelle |
| vieux | vieil | vieille |