This is a well-known garden Corydalis (still called by everyone Corydalis, but I try to be botanically correct) with bluish-green foliage and abundant yellow, fragrant flowers from late spring throughout the summer.
Some say it is weedy, sowing around too much, which is true, but it happens only in very favourable conditions. It is very easy to remove if in excess, and in cold winter climates not all of them survive anyway. I nurtured the nice exemplar in the image just to collect seeds in view of our imminent garden move. It may act as a weed only if you have it in the first place ;)
It will grow in almost any conditions, but does best in part- shaded places with plenty of moisture (but well drained).
Germination: like with other Corydalis, seeds are equipped with elaiosomes and germinate easily if kept moist (warm/cold cycle).