How do you form the French imperative?

Take the present-tense form for tu, nous, or vous, and drop the subject pronoun. For -er verbs, also drop the final -s on the tu form: tu parles -> parle (speak!). For -ir and -re verbs, no -s drop: tu finis -> finis (finish!), tu prends -> prends (take!). Same rule for nous: parlons (let's speak), finissons, prenons. And for vous: parlez, finissez, prenez. Three verbs are irregular: avoir -> aie / ayons / ayez, etre -> sois / soyons / soyez, savoir -> sache / sachons / sachez.

Where do pronouns go with French commands?

With affirmative commands, pronouns attach to the verb with a hyphen, and 'me' becomes 'moi', 'te' becomes 'toi'. Donne-moi le livre (give me the book), assieds-toi (sit down), allons-y (let's go), prenez-en (take some). With negative commands, pronouns return to their normal preverbal position: ne me donne pas le livre, ne t'assieds pas, n'y allons pas. The affirmative-negative split for pronoun position is one of the cleanest catch points in French commands.

French Imperative

The French imperative comes in three forms - tu, nous, vous - covering "you" (informal singular), "let's", and "you" (formal or plural). Take the present-tense form, drop the subject pronoun, and you're mostly done.

The three forms

For most verbs, the imperative is just the present tense without the subject pronoun.

Parler (-er):

(tu) parle - speak
(nous) parlons - let's speak
(vous) parlez - speak

Finir (-ir cluster):

(tu) finis - finish
(nous) finissons - let's finish
(vous) finissez - finish

Attendre (-re cluster):

(tu) attends - wait
(nous) attendons - let's wait
(vous) attendez - wait

The -er drop-the-s rule

For -er verbs only, the tu form of the imperative drops the final -s from the present tense.

present: tu parles -> imperative: parle
present: tu manges -> imperative: mange
present: tu travailles -> imperative: travaille

The drop is silent in speech (the -s wasn't pronounced anyway) but matters in writing. -ir and -re verbs keep the -s: tu finis -> finis, tu prends -> prends.

The same rule applies to aller: tu vas -> va.

The three irregulars

Three verbs have irregular imperative forms. Memorise them.

Verb	tu	nous	vous
avoir	aie	ayons	ayez
etre	sois	soyons	soyez
savoir	sache	sachons	sachez

Examples:

Sois sage. (Be good.)
N'aie pas peur. (Don't be afraid.)
Sachez que je suis la pour vous aider. (Know that I'm here to help you.)

Pronoun attachment with affirmative commands

With affirmative commands, pronouns attach to the end of the verb with a hyphen. Me becomes moi, te becomes toi.

Donne-moi le livre. (Give me the book.)
Dis-le-moi. (Tell it to me.)
Assieds-toi. (Sit down.) - reflexive imperative
Allons-y. (Let's go.)
Prenez-en. (Take some.)
Levez-vous. (Stand up.)

The order when two pronouns attach: direct before indirect, then moi / toi at the end.

Donne-le-moi. (Give it to me.) - direct le before indirect moi
Apporte-les-nous. (Bring them to us.)

Pronoun position with negative commands

With negative commands, the pronouns return to their normal preverbal position and moi / toi revert to me / te.

Ne me donne pas le livre. (Don't give me the book.)
Ne t'assieds pas la. (Don't sit there.)
N'y allons pas. (Let's not go there.)
N'en prenez pas. (Don't take any.)

The split is mechanical: affirmative = pronoun after verb with hyphen and moi / toi; negative = pronoun before verb in normal position with me / te.

The vowel-buffered -er forms

When a pronoun starting with a vowel attaches to an -er tu imperative, the -s comes back to make pronunciation smoother. This applies to y and en specifically.

Va (go!) but Vas-y! (go on!)
Mange (eat!) but Manges-en (eat some of it)

This is purely phonetic - the -s links to the following vowel.

Common imperative phrases

A small set of imperative phrases you'll meet constantly. Worth memorising as units.

Ecoute / Ecoutez. (Listen.)
Regarde / Regardez. (Look.)
Viens / Venez. (Come.)
Attends / Attendez. (Wait.)
Vas-y. / Allez-y. (Go on.)
Allons-y. (Let's go.)
Dis-moi. / Dites-moi. (Tell me.)
Excuse-moi. / Excusez-moi. (Excuse me.)
Asseyez-vous. (Sit down.) - formal
N'oublie pas. / N'oubliez pas. (Don't forget.)
Fais attention. / Faites attention. (Be careful.)

Worked examples

Parle plus lentement, s'il te plait. (Speak more slowly, please.)
Mange tes legumes. (Eat your vegetables.)
Ecris ton nom ici. (Write your name here.)
Allons au cinema! (Let's go to the cinema!)
N'ayez pas peur. (Don't be afraid.)
Donne-le-moi tout de suite. (Give it to me right now.)
Ne te leve pas. (Don't get up.)

Common mistakes English speakers make

Keeping the -s on the -er tu imperative: parles is wrong as a command, it's parle. Using me and te after an affirmative command: donne-me is wrong, it's donne-moi. And forgetting that pronouns swap position between affirmative and negative: ne donne-moi pas is wrong, it's ne me donne pas.