French uses the masculine plural as the default when a group includes at least one male. This applies to pronouns, adjectives, and past participles.

the basic rule

If a group has both males and females, the pronoun is ils, even if there is only one male.

• Marie et Paul sont là. Ils arrivent. “Marie and Paul are here. They are arriving.”
• Quatre-vingt-dix-neuf filles et un garçon sont partis. Ils sont déjà loin. “Ninety-nine girls and one boy left. They are already far away.”

This rule is standard in modern French.

when to use elles

Use elles only when the group is entirely female.

• Les filles sont prêtes. Elles partent. “The girls are ready. They are leaving.”
• Marie et Sophie arrivent. Elles sont en avance. “Marie and Sophie are arriving. They are early.”

The moment a male is present, elles is no longer used in standard grammar.

agreement with adjectives

Adjectives follow the same rule. A mixed group takes the masculine plural form.

• Marie et Paul sont contents. “Marie and Paul are happy.”
• Les filles sont contentes. “The girls are happy.”

Even one male triggers the masculine plural ending.

agreement with past participles

Past participles used with être also follow this pattern.

• Marie et Paul sont partis. “Marie and Paul left.”
• Les filles sont parties. “The girls left.”

With avoir, agreement depends on the direct object, but if it refers to a mixed group, the masculine plural is used.

• Les personnes que j’ai vues sont arrivées. “The people I saw have arrived.” (all female)
• Les personnes que j’ai vus sont arrivées. “The people I saw have arrived.” (mixed group)

why this rule exists

French grammar developed from Latin, where the masculine form often served as the default in mixed groups. This pattern became fixed over time and remains the standard rule today.

current usage and variation

In everyday French, this rule is still the norm in both speech and writing.

You may also see other approaches, mostly in informal or activist contexts:

• repeating both forms
  • Ils et elles sont prêts. “They are ready.”
• using a neutral-style form such as iels
  • Iels arrivent. “They are arriving.”

These forms are not part of standard formal French. They are not accepted in most exams or official writing.

summary

• a mixed group takes ils, even with one male
• elles is used only for all-female groups
• adjectives and past participles follow the same pattern
• the rule is standard in modern French
• alternative forms exist but are not widely accepted in formal contexts