Long light at 48.9° North
Paris runs from about 8 hours 15 minutes of daylight in December to 16 hours 10 minutes in June. The city sits east of its time zone (UTC+1 despite the solar meridian at Greenwich), so summer sunsets land after 21:55 CEST — the long Parisian evenings that fill the quays until late.
Golden hour on the Seine
Paris summer golden hours stretch beyond an hour, and the city's east-west river axis means low sun rakes down the Seine in both morning and evening — the reason so many classic bridge shots happen in the hour either side of sunset. Winter compresses everything: by mid-December the sun sets before 17:00.