How do I resolve 'Your request has been blocked' error from a French website on Safari?

You need to talk to the web site in question to understand why they blocked you. There could be many reasons.

They might not like your location, so are blocking you based on location.

They might not like your IP address because other people within similar addresses have been abusing their site.

There might be some technical problem and it's nothing personal.

There's nothing in your post that helps answer the question directly.