Hi
Growing at latitude 49°N (which corresponds to the northern half of France, Belgium, or southern Germany/Canada) imposes strict time constraints because of the autumn which arrives quickly and coolly.
The onset of flowering (Feminized Seeds / Photoperiodic)
At this latitude 49°N, the days begin to shorten significantly from the summer solstice (June), but the critical signal of 12/12 light (or rather the photoperiod threshold specific to the plant) is generally reached in August.
Start of flowering (The stretch), for most photoperiod varieties, flowering will begin between August 10 and 25.
Appearance of the first visible pistils: You will start to see real little white pompoms towards the end of August / very beginning of September.
here is also what exists
FF (fast flowering) seeds.
they have a shorter time for flowering. I hope this will help you.
and autoflowering generally around 3 months it is finished. no need for 12/12 light time.
I hope this will help you. best wishes