Not really sure what your question is. I think there is a little getting lost between the French and English.
Importing photos into Photos does not create Events (Albums). Photos go into the main library. The main view (Photos Moments) view is sorted by date of the picture and the All Photos Album is sorted by date added.
If you are trying to create slideshows without creating albums, select the photos you want in a slideshow, then choose Create Slideshow from the menu under File. You can select multiple photos either by using the shift key to select photos in in sequence, or with the command key to select individual photos out of sequence. You can do this from the Photos Moments view or from Albums.
The slideshows will be created in Projects.
If this doesn't answer your question, I'm just not understanding what you are asking.