future perfect tense

Verbs that use être in the past ("House of Être" verbs, reflexive verbs) also use être in forming the present perfect. For example, je serai venu(e) uses the future of être because of the action verb, venir (to come), which uses être in the past.
To form the future form of the auxiliary verbs, one uses the future stem and adds the endings -ai, -as, -a, -ons, -ez, -ont. Both avoir and être have irregular future stems; while, with the exception of -re verbs, most verbs use the infinitive as the future stem (e.g. je parler ai, I will speak), the future stem of avoir "is" aur, and that of être is ser.
To form the past participle in French, one usually adds -é, -i, and -u to the roots of -er, -ir, and -re verbs, respectively. However, there are many exceptions to this rule, including these commonly used ones (and all of their related verbs):

• faire: fait
• mettre: mis
• ouvrir: ouvert
• prendre: pris
• venir: venu

Verbs related to mettre ("to put"): promettre ("to promise"); to ouvrir: offrir ("to offer"), souffrir ("to suffer"); to prendre ("to take"): apprendre ("to learn"), comprendre ("to understand"); to venir ("to come"): revenir ("to come again"), devenir ("to become").
When using être as the auxiliary verb, one must make sure that the past participle agrees with the subject: je serai venu ("I [masc.] will have come"), je serai venue ("I [fem.] will have come"); nous serons venus ("We [masc. or mixed] will have come"), nous serons venues ('We [fem.] will have come"). Verbs using avoir do not need agreement.
To make this form negative, one simply adds ne (n' if before vowel) before the auxiliary verb and pas after it: je n'aurai pas parlé; je ne serai pas venu. For reflexive verbs, one puts the reflexive pronoun before the auxiliary verb: from se baigner ("to take a bath"), je me serai baigné; negative: je ne me serai pas baigné.