Honestly just doing a Google search about what you want to do makes a page from this website appear, and it is usually very detailed while having a small "quiz" at the start to filter the information based on your situation. It's not just for life events, but for basically any public French administrative work. You'll have pages about your car, about your job, or if you want to immigrate, and so on.

At the bottom you also have other relevant links (usually to the website of the specific administrations of what you want to do) including reference to the current law that the page is based on (https://legifrance.gouv.fr is also great)

For what I used it for, it was never ambiguous in determining your situation