People take photos during their visit to the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year. (Photos: Xinhua/Gao Jing)

A staff member checks the information of visitors at the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

A visitor takes photos at the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

People line up to visit the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

People pose for photos during their visit to the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

A man takes photos for his sons during their visit to the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

People visit the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

The Elysee presidential palace is pictured in the morning before its opening to the public in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

Musicians perform for visitors at the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

A board reminding people to wash hands is seen at the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

People take selfies during their visit to the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

The Elysee presidential palace is pictured in the morning before its opening to the public in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

A reminder of social distancing is seen at the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

People visit the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

People visit the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

The Elysee presidential palace is pictured in the morning before its opening to the public in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

Members of an honor guard get ready at the Elysee presidential palace before its opening to the public in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.

People take photos during their visit to the Elysee presidential palace in Paris, France, Sept. 19, 2020. Some historical sites are opened to the public this weekend in France to mark the European Heritage Days, a cultural event held in September each year.