Probably Urtica incisa, which has leaves 5-12 cm long, and unbranched, often very long, flower clusters. However, it could also be Urtica urens, which has leaves mostly 1-5 cm long, and shortish branched flower clusters. Please comment.
I would say this is Urtica incisa, which has lanceolate leaves, sometimes with some ovate leaves. Urtica urens has ovate leaves and the shorter flower clusters.