Thank you for all your replies (hadn't received a notification for some reason).
My husband found out that pine tar - or tar had been banned in EU for a while, and then taken of the list again, when they discovered that it was harmless. Meanwhile chemical wood protecting has never been taken off the shelves, and now that is what people buy (the shopkeeper even told me that tar was not allowed). Well well, could look like corporate interests or something (you may call me a conspiracy theorist

, I won't be offended).
We've bought powdered natural dye for linseed oil in Denmark. Somehow having our family friend travel w. Several liters of liquid tar in his suitcase didn't seem like a good idea...the department of culture has a great website about paints that are used in old buildings, how to make them yourself - but we found a Danish shop called 1-2-3linolie (linseed oil) - and they had all thing natural, including dye.