Linux file system audit?

Question

linux

Hey!
Can anyone suggest a good system for monitoring the file system? Even easier, I need to keep track of 1 folder, know which user opened/deleted/created something.
Needed for sftp.
I included logging in sftp, everything is fine, but it does not show which user did what. I tried to do a lot of left information through audit, there is no information about the user through inotify.
Do not offer other ftp servers, strict condition.

Answer 1

iwatch for tracking the directory, tracking user authorization logs and emails about who logged in at what time in order to compare.
Now, if the user is alone and he has a bunch of keys more difficult, he himself has not yet come up with a solution for the second situation, although the question is worth it.

Answer 2

inotify

Answer 3

The question is actually very relevant. inotifywatch/inotifywait is not suitable, because it does not monitor WHO has changed or deleted the file.
I don't really know, but git is a bit off?