Here is one photo pointed at higher up in the sky and here is a composite image.
The situation captured on the photos is similar to this simulation, made with Halosim by Les Cowley and Michael Schroeder
Circumhorizon arc appears when elevation of the Moon (or Sun) is 58° or more above the horizon. In this case the elevation of the Moon was 66°, which is several degrees more than that of the Sun at noon at summer solstice in the Czech Republic (the inclination of the Moon’s orbit to the ecliptic can position the Moon 5° higher)!
In the same day there was also nice complex display around the Sun:
From Bedřichov u Kralovky, photo by Vladimir Wasserbauer and from Paseky nad Jizerou, photo by Čenda Jirak.
Text: Martin Popek, Lukas Shrbeny
( addition on 10 Jan: more images by Vaclav Fego: 1 - 2 - 3 )