CCleaner deleted a very important folder - a supprimé un dossier très important !
It must be returned - Il faut le restituer !
Your post tells us nothing as it is except that you believe that you have lost a folder.
You must give more information about just what you have done if you want somebody to be able to help you.
To start with:
What operating system are we talking about here? (Windows, Mac, Android?)
What had you been doing when you noticed that the folder had gone missing?
Where was the folder located?
Why do you think that CCleaner has deleted a folder?
What had you run in CCleaner? (Health Check, Custom Clean, Registry Cleaner, something else?)
What operating system are we talking about here? (Windows, Mac, Android?) : Windos 10
What had you been doing when you noticed that the folder had gone missing? Looking for a date in one of its documents
Where was the folder located? In my Documents
Why do you think that CCleaner has deleted a folder? I used CCleaner a few days before
What had you run in CCleaner? (Health Check, Custom Clean, Registry Cleaner, something else?) I thing it's called Health Check
Health Check would not remove a file or folder from your Documents folder. - It just cannot be set up tp do that.
(Custom Clean might be able to - but ONLY if you had specifically made an 'Include' to do that, that is not something that you could do by mistake).
To recap: you noticed that a folder was not where you thought it should be, and because you had run CCleaner some days before you have jumped to the conclusion that CCleaner might have removed it.
CCleaner could not do that. It does not even touch your Documents folder. (Unless you specifically tell Custom Clean to do so).
If you have lost/misplaced the files then that it is because of something else that you have done.
I suggest that you search your hard drive(s) in case you have accidentally dragged the folder somewhere else, it can sometimes happen that you drag a whole folder into another folder by mistake.
If you have somehow deleted the folder by mistake then a file recovery tool, such as Recuca, may be able to get the files back. (as long as the drive is a HDD and not a SSD).
But I'd do a search of your drive first to double check if they are still there or not, and you have just inadvertantly moved them.
PS. You should always make a backup copy of 'important' files, preferably on a removable drive, USB stick, etc., just in case.