Oslo is Europe’s most expensive and the world’s 4th most expensive city, leapfrogging past Zurich and Geneva.
Zurich and Geneva are ranked as the second and third most expensive expat cities in Europe and the 5th and 6th most expensive cities in the world for expatriates as at January 2018. This is due primarily to the strong Swiss Franc as well as due to high rentals and institutionalized high wages.
An interesting observation is that the most expensive cities in Europe are dominated by Non-Euro countries.
https://www.xpatulator.com/cost-of-living-article/Europe-Expat-Cost-of-Living-Comparison_708.cfm