Now I wanna learn how to misgender someone in French.
Let me get you started on the right path. French, like most Romance languages, is heavily gendered, unlike English (which treats most nouns as neutral, but has a fair amount of sex-oriented ones ('businessman', 'policewoman', 'waiter'/waitress' etc.) or usages (such as 'handsome' being usually used for men)). Just like sexes, there are only 2 genders: male and female, and they apply to damn near everything (there are some words that are used for both genders, making them somewhat neutral). Plurals use the male form unless all the nouns it refers to are female; so, if you're listing a thousand things, if one of them is a male noun, you'd use the male form if applicable.
Some basic vocab to get your misgendering started. There may be some mistakes due to brain farts, but most of it should work. Also, never trust a French word/sentence's spelling to sound anything like the real pronunciation:
He: il
Him/her (objective): lui
His: son (also used before female words if they start with vowel sounds)
They (male): ils
She: elle
Her (possessive)/hers : sa
They (female): elles
Man: homme ('h' is silent at the beginning of words)
Woman: femme
Sir/mister: monsieur (plural: messieurs)
Guy: typ
Miss: mademoiselle
Lady: dame
Ma'am: madame
Boy: garçon
Son: fils
Girl/daughter: fille
Male: mâle
Female: femelle
Male singular definite article: le
Female singular definite article: la
"Neutral" singular definite article: l' (nothing to do with gender, it's used before words starting with vowel sounds. You'd say "l'homme" instead of "le homme", for instance)
Plural definite article: les
Every (male, singular/plural): tout/tous
Every (female, singular/plural): toute/toutes
Some: des