In French, there are two forms of the conditional perfect (ak.a. the past conditional). This other post covers the first past conditional. The first and second conditional perfect have the same value but the second form appears like the pluperfect subjunctive.
The second form of the conditional perfect is literary and equates to the first form of the conditional perfect in spoken French. Similar to the first form, it’s often used in si (if) clauses.
Si vous me l’aviez dit, j’eusse su. If you’d told me I’d have known.
Si vous l’aviez dit, j’aurais su. (first form)
J’eusse aimé étudier le chinois. I would have like to study Chinese.
J’aurais aime étudier le chinois. (first form)
Conditional perfect second form conjugations
The second form of the conditional perfect is a compound tense, meaning that it’s formed with an auxiliary verb and a past participle.
avoir verb | être verb | reflexive verb |
parler (to speak) | aller (to be) | se souvenir (to remember) |
j’eusse parlé | je fusse allé(e) | je me fusse souvenu(e) |
tu eusses parlé | tu fusses allé(e) | tu te fusses souvenu(e) |
il/elle eût parlé | il/elle fût allé(e) | il/elle se fût souvenu(e) |
nous eussions parlé | nous fussions allé(e)s | nous nous fussions souvenu(e)s |
vous eussiez parlé | vous fussiez allé(e)(s) | vous vous fussiez souvenu(e)(s) |
ils/elles ils eussent parlé | ils/elles fussent allé(e)s | ils se fussent souvenu(e)s |