Hi Guido and welcome to GoY, possibly a delphinium - I'd wait and see what it looks like when it flowers.

welcome from me too. my first thought was delphinium but there are some hardy geraniums with finely divided leaves too.

My first thought was a Geranium species, too. Hard to define, but it doesn't look quite right for a Delphinium. I've got to check some images, now.... :)

I think that I was at least partially mistaken. The best match that I have found so far is a Monkshood (Aconitum species), which is a first cousin to Delphinium. Beware, though--Monkshood is even more toxic than Delphinium, sometimes even toxic by contact. Just in case, I would use gloves when handling.

Yes could be Monkshood, only way you'll really know Guido is when it flowers. I don't think it is a 'weed' though - which is only a plant in the wrong place :)

I don't think the leaves are right for monkshood. Certainly mine look very different. They are thinner - in fact they look more like the leaves in the bottom left corner of the image.

Hi, welcome to GoY, I think Tugbrethil has it, I agree with Monkshead, Derek.

They look very like some of my geranium leaves.

It has mauvish purple flowers if that helps, thanks for all the welcomes and suggestions!

are the flowers singly or on a tall spike of many flowers?
if singly then I'd go geranium, if on a spike then possibly delphinium.

When I was looking at the images, the different species had different foliage, and some did have very finely divided foliage, as Thepoisongardener relates. Several images had foliage like Guido's, two without the species named, and the others had named different species--that's why I was unsure which species to propose.