I think rather some Vicia (vetch.), so another member of the bean family, but no actual bean/ Phaseolus

There is no sense of scale in the picture but if those pods are about 2cm long it's probably Vicia cracca, Tufted Vetch.

From the size of the nailhead on the lower right margin, I doubt the pods are that small -- probably closer to 2".

Vicia sativa subsp. nigra - pods are not in stalked clusters.

You're right nonmember. V sativa.

Can you help me on the chracteristics of subsp. nigra?

Here is a link that might be useful: Vicia sativa