Banners or Alerts in notifications centre Linked to web threat ! How to get rid of it ?

Hello Apple Community,

First af all, I am french and I didn't wrote in english since a longtime so I hope I will be clear and will do my best to be as clear as possible.

My issue is the following :

A new banner popped up in my screen since today. It is not a fake banner from internet but the one you can choose to allow are not from the notifications centre.

This banner alert myself about many different fake subjects :

• a virus attack and invited me to re-install the virus protection ( that i don't have, of course)
• Some message as "is that you that downloading that files ? (clic to show)"
• etc...

And if I click on it, it's linked to a website call "ismilinstite.com" which is directly recognize as a threat by avast ( because I just installed avast today due to this issue and to see what Avast will do )

And also, I can switch off the banners as it is a normal one !!

I don't know where it came from, what is the application related to that ( because it is inside the notification centre )

So, is there somebody who know what it is and how I can get rid of it !!

I hope i am understandable ;)

All the best

Jim