"It is her suitcase that she has lost."
Translation:C'est sa valise qu'elle a perdue.
Umm, wait a moment, don't past participles only decline if the auxiliary is être?
In this example, we have the relative pronoun que representing the direct object, not the direct object itself. Therefore, the rule is:
When a verb in a compound tense (a tense where an auxiliary verb is required, such as the passé composé) is conjugated with avoir and either the direct object or a pronoun representing the direct object is placed before the verb, the past participle must agree with the direct object.
@sitesurf, You said,"Grammatically speaking, this verb has an indirect object, and this must be reflected in the relative pronoun as well:<pre>
C'est la valise dont elle s'est départie (= of which)</pre>
" Doesn't "que" accomplish that?
Also, even though literary, does "se departir" always have to be followed by "de"? In the word reference example, it's difficult to see that. @ http://www.larousse.fr/dictionnaires/francais-anglais/d%C3%A9partir/23592?q=departir, it does say,"se departir de".
"que" is the direct object relative pronoun and "de que" is incorrect. When "de+que" is needed, please use "dont".
"départir qqch à qqun" with the meaning of "to assign stg to sb" is never used.
"se départir de qqch" with the meaning of "to lose stg" is literary and rarely used, except in set phrases like "se départir de sa bonne humeur" (to lose one's good mood).
Good question. First see fartspeed's response, which is absolutely correct.
Then, just for the record, I'd like to add that past participles also decline when they're being used as adjectives (just like any adjective would), e.g. la porte ouvert*e "the open door" which declines for gender, or les carreaux poli*s "the polished tiles" which declines for number.
So to be clear, past participles decline in three situations:
When they're part of the passé composé and the auxiliary verb is être (including reflexive/reciprocal verbs)
When they come after the direct object, regardless of whether or not the auxiliary verb is être
When they're being used as adjectives
EDIT: I really dislike this asterisk-based markup; I wish Duolingo used tag-based like [B][/B] because my asterisks never parse correctly and my greater-than/less-than symbols continually mysteriously disappear.
"C'est LA valise qu'elle a perdue" n'a pas le même sens que "c'est SA valise qu'elle a perdue".
Dans le 1er cas, on montre la valise qu'elle a perdue et qui, manifestement, a été retrouvée.
Dans le 2e cas, on explique que ce qu'elle a perdu, c'est sa valise et pas son parapluie ou la valise de quelqu'un d'autre.