When I see Japan area though Google maps, I see yellowish boundaries. It seems like places where many people are gathered.
I see them in another countries in France
I wonder what data are these and where I can download them
The Discover the action around you with the updated Google Maps blog post may be of interest. The brownish colour refers to Area of Interest, which as they describe:
We determine “areas of interest” with an algorithmic process that allows us to highlight the areas with the highest concentration of restaurants, bars and shops. In high-density areas like NYC, we use a human touch to make sure we’re showing the most active areas.
The article was published in 2018 and may be slightly outdated, but is probably relevant for the most part.
As the data is Google Data, it's unlikely that you'll be able to download it. It's proprietary data and as far as I know, cannot be purchased.