I have D type visa with one schengen transit. I want to know how many days can i stay in the transit country. I'm going to Paris but i want to stop first in Madrid for two or three days. Would i encounter any problems, can i do these with this visa?

Thanks for your help

"Transit" means that you are allowed to stay in Spain just for the time necessary to take the next means of transport going to France.

It is true that Schengen countries usually show some flexibility, but you cannot count on that.