The Dead-nettle Leaf Beetle (Chrysolina fastuosa) looks very similar to the Tansy Beetle (Chrysolina graminis).
However, the latter is much bigger (8-11 mm) whereas the Dead-nettle Leaf Beetle is 5-7 mm.

1st & 2nd photo: Molenpolder Nature Reserve, The Netherlands, 27 July 2011
3rd & 4th photo: Staverden, The Netherlands, 26 July 2016
5th photo: Drentsche Aa National Park, The Netherlands, 7 July 2020