Hi,
My french is pretty bad, I only understand the title. Are you using Windows 10? I had the same problem when I upgraded from Windows 7 to 10.
This fixed the problem for me:
"I rencently upgraded from Win 7 to Win 10 and found the launcher would consitently crash after a few moments making the game impossible to play. Searching the Internet I found that the free ‘Upgrade’ version of Win 10 causes problems with Unreal Engine. The work around for this is to add a small bit of code to your launcher. Right click your desktop shortcut and go to Properties. Add a space after the Target path followed by -http=wininet.
My launcher Target looks like this: “C:\Program Files (x86)\Epic Games\Launcher\Portal\Binaries\Win64\EpicGamesLaun cher.exe” -http=wininet
Do that and you can download and play Paragon no problem."
Source:
And a small advice:
If you want other people to help you, you should make that as easy as possible for them. With other words: Use english instead of french.
And you could have fixed this by yourself by googling the error in english.