"in" pronounced as "in" (like in "English"):
* inutile: useless
* insérer: to insert
* intime: intimate
* incroyable: incredible
* indécis: indecisive
* invisible: invisible
* innocent: innocent
"in" pronounced as "an" (like in "fan"):
* fin: end
* brin: blade (of grass)
* vin: wine
* singe: monkey
* pingouin: penguin
* cinéma: cinema
* minuit: midnight
* pin: pine tree
* brinquebaler: to shake violently
"in" pronounced as "en" (like in "pen"):
* afin: so that, in order to
* chemin: road, path
* marin: sailor
* printemps: spring (season)
* main: hand
* pain: bread
* vain: vain
* sein: breast, bosom
Other:
* qu'il: that he/she
* quinzaine: fortnight (two weeks)
* quincaillerie: hardware store
This is just a small sampling! There are many more French words containing "in". If you have a specific type of word in mind (e.g., verbs, nouns, adjectives), let me know and I can give you more targeted examples.