About 500,000 French have taken part on the protests, and about 3-7 million Americans took part in the February No Kings protest. There's a wide range of estimates on actual participation, but it's fair tonsay that with only 5 times the population the US had at least as much participationper capita.
But the US is 18 times the area of France, so they couldn't centralize it. Instead we got a few good crowds of 100,000+ going in major cities like New York and LA, and thousands of smaller protests around the country.
The US protests looked small, but were massive.