Participe passé invariable : verbes de mesure

In French, when you use the passé composé with the verb avoir, you usually don't change the ending. However, there is a famous rule: if the direct object comes *before* the verb, you must make it agree. For example, in the sentence "The apples that I ate," you would usually add an s. But verbs of measurement are different. Words like kilos, euros, or minutes aren't actually direct objects. They are what we call adverbial complements. They tell us "how much" or "how long," not "what." Because they aren't true objects, the verb doesn't care about them. It stays in its neutral, masculine singular form. It's like a grammar traffic light that stays green no matter who is crossing the street. You don't need to stop and think about whether the kilos are masculine or feminine. The verb pesé is going to stay pesé no matter what. It simplifies your mental load significantly when you're trying to describe your last shopping trip or your height.

1. 1Start with your subject (like Je, Tu, or La valise).
2. 2Add the helping verb avoir in the present tense.
3. 3Add the past participle of your measurement verb (like coûté, pesé, or mesuré).
4. 4Stop right there. Do not add an e. Do not add an s.
5. 5Finish your sentence with the amount or the measurement.
6. 6If the amount (like les dix euros) comes before the verb, still do nothing. The verb remains unchanged.

Use this rule whenever you are talking about literal, physical measurements. If you are at a market in Paris and you're talking about how much your fruit weighed, use this. If you are describing how many kilometers you ran this morning (good for you, by the way!), use this. It applies to price (coûter, valoir), weight (peser), length or height (mesurer), and duration (durer, vivre). Imagine you are at a job interview and you need to say you lived in Lyon for three years. You would say J'ai vécu trois ans à Lyon. Even if you are talking about les trois années (feminine plural), the word vécu stays exactly as it is. It's perfect for everyday situations like ordering food by weight, talking about your commute, or explaining how much that beautiful new jacket cost you. It keeps your speech flowing without the stutter of checking for agreements.

This is where it gets a little bit tricky, but don't worry. This "no-agreement" rule only applies when the verb is used in its literal sense. If you use these verbs figuratively, they behave like normal verbs. For example, if you say "The efforts this work cost me," the word "cost" isn't about money anymore. It's about a figurative price. In that case, you *would* use agreement. But as an A1 learner, you will almost always be using these in their literal sense. Are you talking about actual euros? No agreement. Actual kilos? No agreement. Actual centimeters? No agreement. If you stick to numbers and physical reality, you are safe. Think of it like this: if there’s a ruler or a calculator involved, the verb is probably invariable. If you're being poetic or dramatic, that's when the rules change. But let's save the drama for later levels!

The most common mistake is being too good at grammar. You learn that French usually requires agreement, so you try to be helpful and add an s to coûté when talking about les cent euros. Resist the urge! Another mistake is getting confused by the word que. In a sentence like Les dix euros que ça m'a coûté, many people want to make coûté agree with euros. It feels natural because que is right there, pointing at the euros. But remember: those euros are a price, not a thing you bought. They are an adverbial complement. Don't let the que ghost haunt you. Just keep the verb simple. Also, watch out for the verb peser. If you are weighing yourself, it's a measurement (no agreement). If a chef is weighing ingredients, it's an action (agreement might happen). But for 99% of what you'll say at A1, just keep it invariable.

Compare this to a normal action verb like acheter (to buy). If you say "The apples that I bought," you write Les pommes que j'ai achetées. Why? Because you can "buy an apple." The apple is the direct object. But you cannot "cost an euro." The euro is just the value. It's a subtle difference, but it's the reason for the rule. Think of action verbs as "active" (they do things to objects) and measurement verbs as "descriptive" (they just tell us the size of things). Normal verbs are like builders moving bricks; measurement verbs are like thermometers just telling you the temperature. The thermometer doesn't change based on who is looking at it, and these verbs don't change based on what they are measuring.