les pronoms sujets

A pronoun replaces a noun in order to avoid repetition, just like in English.  Rather than saying “Elise found Elise’s hat under the bed,” we say “Elise found her hat under the bed.”

Subject pronouns are subjects of verbs:  I, you, she.... In French, a subject pronoun is immediately or almost immediately followed by its verb. Just like in English, the use of subject pronouns is required in French.

 Subject pronouns are labelled by the term 'person', referring to the subject's role in the conversation. 1st  person refers to the person(s) speaking (I, we); 2nd person to the person(s) spoken to (you); and 3rd person to the person(s) or thing(s) spoken about (he, she, it, they).

Here are the French subject pronouns:

je:  

Unlike the English pronoun 'I', je is not capitalized unless it begins a sentence.

tu:  

The pronoun tu is singular and, importantly, informal. Use tu to address people your own age and those you know well; also animals and children. Calling an older person, a stranger, or your boss “tu” would be seen as rude.

on:

The pronoun on means 'one', or 'they' in a nonspecific sense: 'comme on dit' (as they say). On often replaces 'nous' in spoken French: 'On y va?' (Shall we go?).

vous:

The pronoun vous is conjugated with a plural verb so it often refers to more than one person. However, it is also the customary form of address when you are talking to only one person you do not know well, such as an elder, a boss, a cashier, a waitress, a doctor, etc: all people you do not know well, or as a sign of respect. Using te tu form in these situations is considered a sign of disrespect. 

Lena: Bonjour, Mr. Sanchez. Vous allez bien? Lena: Hello Mr. Sanchez Are you doing well?

Mr. Sanchez: Ah, oui! Et vous et votre famille, vous allez bien? Mr. Sanchez: Ah, yes! And you and your family, are you doing OK?

il/ elle:

Il and elle besides meaning 'he' and 'she' can both express the meaning 'it' depending on the gender of the noun being replaced. For example:

La musique est bonne, n'est-ce pas? The music is good, isn't it?

Non, elle est terrible! Je déteste la musique classique. No, it's terrible. I hate classical music.

ils/ elles:

Ils and elles are similar to il and elle since they agree with the gender of the noun they replace. Ils and elles  may refer to people or things. 

• Elles is used to mean 'they' if  it replaces people who are all women or to objects that are all feminine in gender. 

• Ils is used to mean 'they' for objects that are masculine in gender or a group of men or any group where it’s not clear if there are both masculine and feminine objects.