After deleting files with the Find Duplicates tool, there is a restore button available.
However, once the application is closed, it isn't possible to automatically restore deleted files into their original location: after opening Trash and right-clicking the deleted files, there is no Put Back button.
This behavior is due a known macOS issue discovered a while back ( https://openradar.appspot.com/41878624 ) that makes the system "forget" original locations of files that have been deleted programmatically.
Hence, restoring them to that original location automatically becomes impossible. However, you can still manually restore files by moving them from the Bin into their corresponding folders.