Hi @rupach ,
Do you want to send an email notification when a folder is empty?
Please check the following flow configuration for a reference.
Add the trigger. Here I am using Button, you could change it to a Recurrence to your scenario.
Get files (properties only) from the specific library.
Add a Condition to check if the file name contains a ‘.’ Or not:
File name with extension (dynamic content) does not contain .
Under if yes branch, add action List folder. Select dynamic content Identifier from the previous action.
Add Condition 2 with the following code:
empty(body('List_folder'))
is equal to
True
Under If yes branch of Condition 2, add action Send an email to notify the user.
Images like below for your reference.


Best regards,
Mabel