Hello Sylvain,
I am sorry for the late reply.
From your screenshot, I can see that all recaptcha settings are configured correctly but however, can you provide us with backend access and ftp access so that we can further debug this issue and have a better understanding of this issue. There are several reason why recaptcha doesn't get displayed in your site and so that we need your site access in order to investigate this issue. I am for the inconvenience caused and hope you can understand.
Please be advise.
Thanks.