I. Verbs conjugated in the present perfect with "to be" as the auxiliary
I am become Death, destroyer of worlds.
--the Bhagavad Gita, as quoted by scientist Robert Oppenheimer, one of the "fathers" of the atomic bomb
You don't hear it much in modern English, but in older English, it was common for some verbs, especially verbs of
motion and verbs of
change of state, to be paired with "to be" instead of "to have" in the past tense. The above Oppenheimer quote is an example of this:
"I am become Death" instead of
"I have become Death." In Stephen R. Donaldson's
The One Tree, a powerful character named Infelice arrives at a gathering and announces her presence by saying:
I am come.
This should alert you to the fact that not all verbs are conjugated in the present perfect with the auxiliary (i.e., helping verb) "to have." There are verbs that take "to be" as their auxiliary.
II. La maison d'être
In modern French (and in German, too, by the way*), a certain set of verbs is still conjugated in this manner. French teachers teach these verbs in several different ways, but one of the more prominent ways (aside from invoking "MRS. D.R. VANDERTRAMPP"**) is to use a visual aid called
"La maison d'être," or "the House of
être." See below:

(reference found here)
III. Some quirks of être verbs
As in older English, French
être verbs (henceforth "E-verbs") are those that involve
motion or a
change of state. When you conjugate an E-verb
au passé composé, the past participle must agree with the gender and number of the subject. To wit:
Je suis monté(e)
Tu es monté(e)
Il est monté
Elle est montée
Nous sommes monté(e)s
Vous êtes monté(e)(s) (remember, with "vous," this could be singular!)
Ils sont montés
Elles sont montées
Another quirk to remember is that certain E-verbs can also be conjugated with
avoir if they're transitive (i.e., transferring their action from the subject to an object or objects;
see here for more info). Some E-verbs that can also be A-verbs:
passer: J'ai passé le livre à mon frère. (I passed the book to my brother.)
descendre: J'ai descendu les bagages. (I took down the bags.)
(Or, more sinisterly) J'ai descendu le flic. (I killed the cop.)
sortir: J'ai sorti la poubelle. (I took out the garbage.)
monter: J'ai monté mon sac à dos. (I've put up my backpack.)
There are others, but you get the idea. If the E-verb is being used transitively, i.e., with an object, then it's actually an A-verb in that context. Be very careful with this!
IV. Les verbes pronominaux et les verbes réfléchis: pronominal and reflexive verbs
There is an entire class of verb that is always conjugated with
être: le verbe pronominal. A subtype of this verb is
le verbe réfléchi, or reflexive verb. In the infinitive form, such verbs have the pronoun "se" in front of them.
The pronoun
se normally means something like "(to) oneself/each other," but sometimes there's no good reason for the
se to be there. In such cases, the pronoun
se is simply a pronoun and implies no reflexivity. A good example of this is the verb
s'apercevoir, to notice/realize, which can be both pronominal and reflexive.
PRONOMINAL: Elle s'aperçoit que son mari n'est pas revenu. (She realizes that her husband hasn't come back.)
REFLEXIVE: Elle s'aperçoit dans la glace. (She notices herself in the mirror.)
Elle s'est aperçue que son mari n'était pas revenu. (She realized her husband hadn't come back.)
Elle s'est aperçue dans la glace. (She noticed herself in the mirror.)
As you see above, the
se plays no real role in the pronominal sentence.
Now look at the following
reflexive verbs:
Ils se parlent. = They talk/speak to each other.
Ils se sont parlé. = They talked/spoke to each other.
Elles se voient. = They (fem.) see each other.
Elles se sont vues. = They saw each other.
Elle se parle. = She talks to herself.
Elle s'est parlé. = She talked to herself.
Did you notice something? In the above
se parler examples, the participle
parlé did NOT receive an "e" or an "s"! Why? Because in this instance, the pronoun
se is an
indirect object. The original verb is
parler à [quelqu'un], so
parler takes an indirect object. You can see this when
parler is used non-reflexively:
Je parle à Jeanne. Je
lui parle. (lui = indirect object)
J'ai parlé à Jeanne. Je
lui ai
parlé. (not "Je lui ai
parlée.")
Je parle à Jeanne et Hélène. Je
leur parle. (leur = indirect object)
J'ai parlé à Jeanne et Hélène. Je
leur ai
parlé. (not "Je leur ai
parlées.")
Compare this to the past-tense rule for direct objects, where there is agreement in gender and number:
J'ai vu Jeanne hier. (Jeanne = direct object)
Je
l'ai
vue hier. (the participle is inflected as feminine singular)
Let's look at an example with a reflexive verb:
se donner des cadeaux = to give each other gifts
Ils se donnent des cadeaux. (présent)
Ils se sont donné des cadeaux. (passé composé)
Why not "se sont donnés," with an "s" at the end? Because the direct object is
cadeaux, while
se (each other) is the indirect object. No agreement necessary.
V. L'intérrogation! (The quiz!)
Ecrivez la bonne locution
au passé composé.
1. Elle _____ (se voir) dans la glace.
2. Ils _____ (se donner) des compliments.
3. Il _____ (tomber) de la falaise (cliff).
4. Elle _____ (naître) en 1995.
5. Vous _____ (passer) par le même bâtiment trois fois!
6. Je lui _____ (passer) le sel.
7. Nous _____ (monter) les valises.
8. Elles _____ (descendre) de la montagne.
9. Ils _____ (aller) voir leur famille en France.
10. Tu _____ (sortir) le chien?
LES REPONSES (highlight the space between the brackets to see the answers):
[
1. s'est vue
2. se sont donné (no "s"!!)
3. est tombé
4. est née
5. êtes passé/passée/passés/passées ("vous" can be sing., pl., masc., fem.)
6. ai passé
7. avons monté
8. sont descendues
9. sont allés
10. as sorti
]
Vous avez eu 10 sur 10, j'espère...!
*German examples:
Ich bin gekommen. = I have come. (not
Ich habe gekommen.)
Er ist gegangen. = He has gone. (not
Er hat gegangen.)
**The mnemonic "MRS. D.R. VANDERTRAMPP" is an acrostic for remembering a cluster of
être verbs. To wit:
Monter (motion)
Rester (motion, or lack thereof)
Sortir (motion)
Devenir (change of state)
Retourner (motion)
Venir (motion)
Aller (motion)
Naître (change of state)
Descendre (motion)
Entrer (motion)
Revenir (motion)
Tomber (motion)
Rentrer (motion)
Arriver (motion)
Monter (motion)
Partir (motion)
Passer (par) (motion)