Directory Monitor can be used for the surveillance of certain directories and/or network shares and will notify you of file changes/access, deletions, modifications, and new files in real-time. Users and processes making the changes can also be detected.
FSMonitor is a macOS app that monitors all changes in the file system, including file creation, deletion, change of content, renames, and change of attributes. It provides different display modes to to examine the list of changed files.
File system/directory monitoring utilities with loggin and task processing support (can execute files or make a WCF service call). Multiple configuration options. Source code libraries can be used to create a custom file system monitor.