August closures in France/elsewhere

Are you asking because of the French August vacation time?
I was in Paris in August one year. All major sites were open and as I was in a short let apartment, I was in a neighbourhood. Merchants seemed to choose 2 weeks of August and others chose the other 2 weeks, so that services were still available. Very amicable.
As to smaller more rural locations, I am not sure.

The short answer is no, they're not closed. Although any site may be closed for maintenance/renovation. This coming August? Who knows. My magic 8 ball is in for maintenance. Again. I think it's from over use.

As one source you might try https://travel.state.gov/content/travel/en/traveladvisories/COVID-19-Country-Specific-Information.html and follow the links to the particular country. There will be some discussion about curfews and what is and isn't open.

In normal years, some restaurants closed in August for vacation. But there were plenty of alternatives open, partly to cater to the summer tourist rush. In 2021, who knows?

August 15th is a French holiday, although most sites were open when we were there in 2018, they may have shorter hours however. Several 'bucket list' restaurants were closed for their summer holiday, but plenty were open. Also check that your accommodation has air conditioning if that's a concern for you. We lucked out, the week before was in 90's but the few days we were there a cold front had come through and it was quite pleasant.

Alpine ski/snowboard slopes aren’t open for sliding down in August, but most, if not all resorts are still open for hiking, sightseeing rides on chairlifts and gondola trams, wildflower viewing, and mountaintop views. They’ve made a winter destination a summertime destination, too.

Iceland’s outdoor sights are more open in the summer than they are in the winter, as they’re more accessible, with some roads only open in summer. The northern lights, though, aren’t visible in August.

August 15 is also a Catholic Holyday in other countries such as Croatia and Poland. In Croatia the buses are free for the day. Most restaurants are open.

I wonder what the original poster has in mind when using the term "major attractions."

Sammy, yes, and where is "elsewhere"? Other French cities, or other countries?