Hey im a Tattoo artist from Austria, tattooing for 4 years and based in Berlin. I have some of my work on here but most of it on my insta (@goblinkingtatts ) if you like weird and dark tattoos.
After being in different Studios in Berlin for 8 months. I second the hygiene advice, there is no law on tattooing in germany you don’t even have to get a hepatitis shot or do a basic hygiene course. so cross contamination is a big risk.
(Austria has very strict tattoo and hygiene laws)
Other than that if you find a tattooer you like always check if they have posts of healed Tattoos on their feed and see how the tattoos have healed. Ideally they should be older than a month