The comet C/2023 A3 Tsuchinshan-ATLAS is nicely visible from central France. The best time to observe it currently is shortly after 20:00 CEST, i.e. about 50 minutes after sunset and roughly 30 minutes before it sets.

It becomes visible in the West at low elevations above the horizon (10-15 degrees). It was too faint tonight to see it with the naked eye against the twilight and other light pollution, but a high-ISO or long-exposure photo captures it quite nicely, including its tail that spans several degrees across the sky.

In other words, observe it the closer to the start of astronomical twilight the better, while the comet is still high enough in the sky.

The photo below is a hand-held, high-ISO image I captured from a park nearby. It would have been better to use a tripod and expose for longer at a lower ISO, but oh well! The comet (bright nucleus) and its tail are faintly visible in the bottom left quarter of the photo.