The Conditional Perfect

The conditionnel passé is the tense of what did not happen. J'aurais aimé venir: I would have liked to come, and I did not.

If you can build a present conditional and a passé composé, you already know the form. Everything genuinely new on this page is about use, and the uses are more varied than most courses let on.

Formation: nothing you have not met

Conditional of avoir or être + past participle. That is the whole rule.

Two carry-overs, both from the passé composé and neither of them new:

• The auxiliary choice is the same. Anything that takes être there takes être here: elle serait venue, ils seraient partis, nous nous serions levés.
• The agreement rules are the same. être verbs agree with the subject, reflexives follow suit, and avoir verbs agree only with a preceding direct object: la lettre que j'aurais écrite.

Job one: the unrealised past

The core use, and the one that needs no scaffolding around it. Something was possible, and it did not come off.

• J'aurais aimé venir. (I would have liked to come.)
• Elle serait restée plus longtemps. (She would have stayed longer.)
• On aurait pu gagner. (We could have won.)
• Ça aurait été plus simple. (That would have been simpler.)

Notice that not one of these has a si clause. French does not need one, any more than English needs an "if" to say "I would have come". The condition is in the air, and everybody can reconstruct it. This is by a distance the commonest way the tense appears in speech, and it is why learners who only meet the tense inside a Type 3 sentence never quite recognise it in the wild.

Job two: the result half of a Type 3 si clause

The si clauses page fixed the three pairings: present with future, imperfect with present conditional, pluperfect with conditional perfect. That third pairing is where this tense earns its formal keep.

• Si j'avais su, je serais venu. (If I had known, I would have come.)
• Si nous étions partis plus tôt, nous n'aurions pas raté le train. (If we had left earlier, we would not have missed the train.)

Rather than repeat the pairing, take it further, because real French frequently drops or disguises the si. Three ways it does that, all of which leave the conditional perfect standing on its own:

With a preposition instead of a clause. The condition becomes a phrase.

• Sans toi, je n'aurais pas réussi. (Without you, I would not have succeeded.)
• Avec un peu de chance, on aurait gagné. (With a bit of luck, we would have won.)
• À ta place, je n'aurais rien dit. (In your place, I would have said nothing.)

With the two halves swapped. The result can come first, and the comma disappears.

• Je serais venu si j'avais su.

With the condition wholly implicit, which is job one above. On aurait pu gagner carries a condition nobody has to state.

What never changes is the golden rule, and it applies in the past as strictly as anywhere: no conditional after si. It is si j'avais su, never si j'aurais su.

Job three: journalistic distance

This one is invisible to learners because no course mentions it and every French newspaper uses it. The conditional marks a claim the writer has not verified.

• L'accident aurait fait trois victimes. (The accident is said to have killed three people.)
• Le ministre aurait démissionné. (The minister has reportedly resigned.)
• Les deux hommes se seraient rencontrés à Lyon. (The two men are said to have met in Lyon.)

English does this lexically, with "reportedly", "apparently", "allegedly", "is said to have". French does it with a tense, which is shorter and carries no fingerprints. The practical consequence for a reader is worth stating plainly: a French headline in the conditional is a hedge. The paper is telling you it has heard this and cannot yet stand behind it. Swap the tense to a passé composé and the claim becomes the paper's own.

You will meet the present conditional doing the same job for present claims, il serait à Paris (he is said to be in Paris), and the conditional perfect doing it for past ones. Same device, two tenses.

Job four: politeness, in the past

The present conditional softens a request: je voudrais un café. The conditional perfect does the same for something you wanted then, or for a request you want to make especially gently now.

• J'aurais voulu vous parler un instant. (I would have liked a word with you.)
• J'aurais aimé savoir si c'est possible. (I was wondering whether that might be possible.)
• Nous aurions préféré la chambre au calme. (We would have preferred the quiet room.)

The last one is the useful pattern: a complaint or a preference expressed in the conditional perfect lands far more softly than the same thing in the present. It is a register move, not a tense move, and it is why hotel receptionists hear it all day.

Job five: the future perfect, seen from the past

The final job is mechanical rather than expressive. In reported speech, a future shifts back to a conditional. A future perfect shifts back to a conditional perfect.

• Direct: Il dit: "J'aurai fini avant midi." (I will have finished before noon.)
• Reported: Il a dit qu'il aurait fini avant midi. (He said he would have finished before noon.)

Note that this sentence contains no hypothesis at all. He fully expected to finish. The conditional perfect here is doing the work of a future perfect that has been dragged backwards by a past reporting verb, and confusing it with the unrealised-past use is a real reading error: il a dit qu'il aurait fini does not mean he failed to finish.

Worked examples

• J'aurais aimé rester plus longtemps. (I would have liked to stay longer.) - unrealised past, no si needed.
• Si tu m'avais prévenu, je serais venu. (If you had let me know, I would have come.) - Type 3, pluperfect then conditional perfect.
• Sans son aide, nous n'aurions jamais fini. (Without his help, we would never have finished.) - the condition is a phrase, not a clause.
• Elle serait partie vers huit heures. - two readings, and only the context decides: either she would have left around eight (unrealised), or she reportedly left around eight (journalistic).
• J'aurais voulu vous demander quelque chose. (I wanted to ask you something.) - politeness.
• Il a dit qu'il serait rentré avant nous. (He said he would be back before us.) - future perfect shifted into the past.
• Les lettres que j'aurais écrites. (The letters I would have written.) - avoir verb, preceding direct object, so the participle agrees.

Common mistakes English speakers make

The error that outranks everything else is si plus a conditional: si j'aurais su. The condition takes the pluperfect, si j'avais su, and the conditional perfect belongs in the other half. Second, the wrong auxiliary, which the English "would have" positively encourages because it offers only one: it is elle serait venue and ils seraient partis, never elle aurait venue. Third, dropping the agreement on être verbs while concentrating on the tense: elles seraient restées, nous nous serions levés. Fourth, reading a journalistic conditional as a hypothesis; le ministre aurait démissionné is a news report, not a might-have-been, and the tense is the only clue. Fifth, mistaking the reported future perfect for an unrealised past: il a dit qu'il aurait fini means he expected to finish. Finally, the plain conditional where the perfect is wanted: je viendrais is "I would come", about now or later, while je serais venu is "I would have come", about a past that is closed. English keeps them apart with one extra word, and so must you.

See also

• The si clauses page covers the three conditional sentence types and the golden rule this tense keeps breaking.
• The j'aurais dû, tu aurais pu page covers the single commonest use of this tense, regret and reproach.
• The conditionnel page covers the present conditional whose auxiliary this tense borrows.
• The plus-que-parfait page covers the tense that opens a Type 3 si clause.
• The reported speech page covers the sequence shift that produces the future-in-the-past use.
• The French grammar cheatsheet covers the whole A1-B2 grammar map at a glance.