Learn French: Parmi la multitude, la différence entre eux est très claire. - Among the multitude, the difference between them is very clear.

This sentence perfectly contrasts the two prepositions! Parmi (among) is used with la multitude because it describes being surrounded by a larger, undefined mass of people. Entre (between) is used with eux because it refers to a direct relationship or comparison between specific, distinct individuals within that crowd.

Why do we use eux after entre instead of the subject pronoun ils?

After prepositions like entre, parmi, avec, or pour, you must always use stress pronouns (sometimes called disjunctive pronouns). For a masculine or mixed-gender group, the correct stress pronoun is eux.

Does entre eux imply there are exactly two people being compared?

Not necessarily! While entre often compares exactly two things (like the English 'between'), it can be used for three or more if those people are being considered individually as distinct entities, rather than as a single collective group.

Why is claire feminine when it directly follows eux, which is a masculine pronoun?