Comment by 1e1a

Potentially related phenomenon: Across multiple locations >200km apart in France, I've personally noticed that mains powered lights reliably and visibly pulse a few times at the beginning of every hour, and half-hour throughout the day. From memory, it's roughly one or two 1-2s long sequences of pulsed dimming, at around 5-10 pulses/second. The pulse frequency doesn't seem to change, and it starts and stops abruptly. Does anyone know what this could be?