Current car number plates in France are formatted 2 alpha- 3numeric -2 alpha (eg, AB-123-BC), not 3alpha - 4 numeric -2alpha (Tara's Opel Insignia is plated HJK-2289-ZZ)
Paris is not built on a grid system, so the US measuring standard of blocks is meaningless. Also, Tara, being British, would never judge distance using that method.