There are strict limitations on 'hate speech’, denial of the Holocaust is illegal, and there are laws still on the books (and some examples of media outlets being prosecuted for breaking those laws) around presenting drug use as a positive thing, or encouraging drug use.
You can be prosecuted as an "apologist for terrorism” should the government conclude that this is what you are doing. You can also be charged with “contempt of public officials” as people were for burning an effigy of President Macron.
In the US, as far as I know as someone who has only ever visited the country for a short time, you are allowed to hold the President in contempt, you can announce to anyone who’ll listen your ignorant, racist, Holocaust-denying opinions and not be afraid of that speech being criminalized (though there are social costs you’ll probably pay), and if you want to go on the internet and encourage people to try drugs, you can. You can support whatever side of whatever conflict around the world you like with your words and you probably won’t be breaking the law.
France’s laws around freedom of expression are strong, but they are different to those in the US and I would say offer fewer protections for citizens than the US 1st amendnment.
In the US and most countries though, there's libel / defamation laws; you can say a lot of shit about people, but they can then sue you for libel / defamation if you spout nonsense.
Those same laws exist here in France, too, even if they are a little more complex. The truth of a statement, for example, is not a sufficient defence if that truth is not something that is public. Making someones private life public, even if your comment is true, can be against the law.
Defamation might be illegal in both the US and France, but I can burn an American flag and show contempt for the US President without commiting a crime the US. Do the same in the France and you don’t have the same protections for your speech.
