Country-wide. It's typically in the 100k's per major city. The last Yellow Vest protest in France was organised in 80 cities & towns.
For an example of underrepresentation, "160k" was the "official" figure for the totality of France recently in the few mainstream media reports. Most "official" figures, if they report at all, are multiple factors low, or in same cases orders of magnitude too low.
Eg, just the single public square in Paris (place de la concorde) protestors have occupied in most protests, easily holds much more than 160k, on its own. That was just one square in one (albeit the biggest) city that day.
Find drone shots or timelapses to make estimates, for example: odysee.com/@alltheworldsastage:0/Aug-7th-Paris---Montpellier-France-Massive-Anti-Vaccine-Passport-Protests-Libert%C3%A9-Manifestations:2?
(Absolutely don't endorse this channel or anything - but this bit of content in this case is largely unedited or editorialised, and is sourced.)
If you find a good visual source, use one of various free crowd estimator tools to see for yourself. Draw lines on the map and drag a slider for crowd density - eg the above-mentioned square in Paris is 50k for a light crowd, up to 200k+ for a packed crowd - and the protests meet the definition of packed.
There are no easily-accessible, centralised and vetted sources of indisputable information during times of widespread censorship - you simply have to go look and do the work of vetting it yourself. Beware sometimes it's mislabelled/misinformation, eg, actually shots of a world cup celebration (likely intended to discredit). It's not hard to be discerning however - if absolutely everyone is holding the countries flag and there are no signs, it's likely a sports or other national celebration. If some are holding flags and others are holding signs saying "liberte" it's a protest. You need to learn the foreign words for freedom and vaccine passport at least.
In Italy it's easy as the word for "no" is the same as English and the word for vaccine passport is "green pass": so "no green pass", as various members of parliament ambushed the center of a parliament session and held up signs saying so recently.
You can bet if multiple members of parliament are flooding the central chamber of government of a major European country with protest signs, then protests are at least in the millions.