When you write 50% of students passed or half the oranges are rotten, you are using a fraction or percentage as the head of a complex subject. The agreement question is: does the verb agree with the percentage (always singular by form) or with the noun being measured? French has a clean and predictable rule for this — agree with the noun being measured, not with the percentage — but it has enough exceptions and special cases that many native speakers hesitate. This page lays out the full system.
The rule is simple in its core: the verb agrees with the second noun in the construction, the one introduced by de / des / du. If that noun is plural and countable, the verb is plural. If it is singular or a mass noun, the verb is singular. From this single rule, almost everything else follows.
The core rule: agree with the second noun
In a structure like X% de Y, the verb's number is determined by Y, not by the percentage.
50% des étudiants ont réussi l'examen cette année.
50% of students passed the exam this year.
The verb ont réussi is plural because étudiants is plural and countable. The percentage 50% is irrelevant for agreement — it is just a quantifier.
50% du temps est passé à attendre.
50% of the time is spent waiting.
Here the verb est passé is singular because temps is a singular mass noun. Same percentage, different verb form, because the noun being measured determines the agreement.
20% de la population française vit en région parisienne.
20% of the French population lives in the Paris region.
Population is a singular noun (and a collective unit at that), so the verb vit is singular. If the construction had been 20% des Français, the verb would have been plural: 20% des Français vivent en région parisienne.
The same rule extends to fractions expressed as words. La moitié de, un tiers de, un quart de, trois quarts de all behave like percentages: agree with the second noun.
La moitié des oranges sont pourries — il faut les jeter.
Half the oranges are rotten — they have to be thrown away.
Un tiers de la classe a obtenu une mauvaise note au test.
A third of the class got a bad grade on the test.
Trois quarts des invités sont déjà partis.
Three quarters of the guests have already left.
The first sentence has plural agreement (sont pourries) because oranges is plural countable. The second has singular agreement (a obtenu) because classe is a singular collective. The third has plural agreement (sont partis) because invités is plural.
"Out of N" constructions
Expressions like trois sur dix (three out of ten), une sur cinq (one in five), deux étudiants sur trois (two out of three students) follow the same logic — agreement with the underlying countable group.
Trois étudiants sur dix ont échoué à l'examen.
Three students out of ten failed the exam.
Une femme sur cinq a déjà été victime de harcèlement au travail.
One woman in five has been a victim of harassment at work.
In these cases, the head of the noun phrase is étudiants / femme, and the sur dix / sur cinq clarifies the proportion. Agreement targets the head: plural with trois étudiants, singular with une femme.
A subtle case: un sur cinq and un sur dix with no explicit noun take singular agreement, because un itself is singular.
Un sur cinq a refusé de répondre.
One out of five refused to answer.
If you want plural meaning, you have to make the head plural: deux sur cinq ont refusé, not *un sur cinq ont refusé*.
Sums of money: agreement with the unit
When the subject is a sum of money or a measurement expressed as a single sum, French treats it as a singular unit, even if the number is plural in form.
Un million d'euros a été dépensé en publicité l'année dernière.
One million euros was spent on advertising last year.
Trois mille kilomètres, c'est trop loin pour un week-end.
Three thousand kilometers is too far for a weekend.
The logic: un million d'euros refers to a single sum; the expression behaves like cette somme (this sum) rather than like des euros (some euros). Same for distances and durations expressed as totals.
This is parallel to English usage: one million dollars was spent (singular, sum) vs one million people were affected (plural, individuals). In both languages, the choice tracks whether the number names a quantity or counts individuals.
But beware: when the same noun is interpreted as countable individuals rather than as a sum, plural agreement returns. Trois mille personnes ont participé (three thousand people participated — counting individuals, plural). Trois mille euros ont été retirés — also acceptable as plural if you visualize the bills, though singular is more common.
On, tout le monde, chacun: invariably singular
Three pronouns override every other rule and lock in singular agreement no matter what they replace.
On takes singular verb agreement, period. Even when it means we and the implied subject is plural, the verb is singular.
On part en vacances la semaine prochaine.
We're leaving for vacation next week. (singular verb)
On a tous compris la leçon.
We all understood the lesson. (singular verb, but plural agreement on the past participle is acceptable)
In the second sentence, on a is the singular verb (no choice), but the implicit we-meaning can license plural agreement on a following past participle: on est arrivés (we arrived, masculine plural). The verb itself, however, never goes plural with on.
Tout le monde is always singular:
Tout le monde est arrivé à l'heure aujourd'hui.
Everyone arrived on time today.
Chacun / chacune is always singular:
Chacun a son avis sur la question.
Each has their opinion on the matter.
Chacune des candidates a présenté son projet.
Each of the candidates presented her project.
These are unmovable. Even if the underlying meaning involves multiple people, the grammatical form is singular and so is the verb.
Plain numerals: simple plural agreement
When the subject is a simple plural numeral with a noun (no fraction or percentage), agreement is straightforward plural.
Deux étudiants ont réussi l'examen avec mention très bien.
Two students passed the exam with high distinction.
Trois personnes attendent à l'accueil.
Three people are waiting at reception.
Cent visiteurs sont entrés ce matin.
A hundred visitors came in this morning.
This is the easy case and matches English exactly. The interesting cases are when the numeral interacts with a fraction or percentage construction.
Le tiers, le quart: with le, agreement is more flexible
When the fraction takes a definite article (le tiers, le quart, la moitié), traditional grammar allows agreement either with the fraction itself (singular) or with the complement (plural). Modern usage tends toward agreement with the complement.
La moitié des élèves ont raté le bus ce matin.
Half the students missed the bus this morning. (modern usage — plural)
La moitié des élèves a raté le bus ce matin.
Half the students missed the bus this morning. (traditional — singular agreement with moitié)
Both are accepted. Plural agreement is now standard in everyday writing and speech. Singular agreement persists in formal and literary registers, where some writers cling to moitié as the grammatical head.
For learners, default to plural when the complement is plural countable. You will sound natural and modern, and you will not be flagged as wrong by any grammar checker.
"Plus d'un" and "moins de deux": notable exceptions
Two specific expressions take counterintuitive agreement.
Plus d'un + singular noun → singular verb (despite the plural meaning):
Plus d'un étudiant a triché à cet examen.
More than one student cheated on this exam.
The logic is grammatical: un étudiant is singular, so the verb agrees with it. The fact that plus d'un means more than one (semantically plural) is overruled by the singular form of un étudiant.
Moins de deux + plural noun → singular verb:
Moins de deux ans s'est écoulé depuis sa nomination.
Less than two years has passed since his appointment.
This one trips up natives. Moins de deux names a duration shorter than two of the unit, and French treats this short duration as singular. Many speakers default to plural here (moins de deux ans se sont écoulés) and few will flag the error, but prescriptive grammars maintain the singular.
When the percentage takes a definite article
A subtle difference: les 50% des étudiants (with the article les) is a different grammatical structure from 50% des étudiants (without). With the article, the percentage itself becomes the grammatical head and triggers plural agreement automatically because les 50% is plural.
Les 50% des étudiants qui ont réussi ont reçu une bourse.
The 50% of students who passed received a scholarship.
In practice, the article-less form is more common, and the rule "agree with the second noun" handles it cleanly. The article-introducing variant appears mostly in formal writing and when the percentage is being treated as a defined group.
Common Mistakes
❌ 50% des étudiants a réussi.
Incorrect — agreement should be with étudiants (plural), not with the percentage.
✅ 50% des étudiants ont réussi.
50% of students passed.
⚠️ La moitié des oranges est pourrie.
Traditional but archaic — singular with moitié is grammatical but sounds stiff in modern usage.
✅ La moitié des oranges sont pourries.
Half the oranges are rotten. (modern default)
❌ Tout le monde sont arrivés.
Incorrect — tout le monde always takes singular agreement.
✅ Tout le monde est arrivé.
Everyone arrived.
❌ Un million d'euros ont été dépensés.
Incorrect for sums — un million d'euros names a single sum and takes singular agreement.
✅ Un million d'euros a été dépensé.
One million euros was spent.
❌ Plus d'un étudiant ont triché.
Incorrect — plus d'un takes singular agreement despite plural meaning.
✅ Plus d'un étudiant a triché.
More than one student cheated.
❌ Chacun ont leur avis.
Incorrect — chacun is singular and forces singular agreement (and singular possessive son/sa).
✅ Chacun a son avis.
Each has their opinion.
Key takeaways
The dominant rule for fractions and percentages is agree with the second noun: with 50% des étudiants, look at étudiants (plural) and use ont; with 50% du temps, look at temps (singular mass) and use est. The exceptions are predictable: sums of money are singular (un million d'euros a été dépensé); on, tout le monde, and chacun are invariably singular; plus d'un + singular noun is singular; and la moitié des X allows both agreements with modern French preferring plural. Once you see the underlying logic — French agrees with the real semantic head, not with the quantifier — every case in the system clicks into place.
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