France is completely different, she is employed either hourly- a maximum of 35 hours/week- or employed daily, ie. 218 days a year (for starters).
EDIT: @nawitus:
Sorry but your data is totally useless for this purpose. 1) it's the whole economy, not just programmers and 2) it includes part time workers! To imply that full-time programmers in London are working on average less than a 40 hour week is so far from reality.
The average hours worked in France is 1500, UK 1600 and USA 1800[1]. Therefore if you factor in hours worked, a developer in France should be paid 83% of average salary in America and 94% of average salary in the United Kingdom. This of course assumes that everything else is equal (which is untrue). A 30k salary in UK should translate into 28k salary in France when you factor in the number of hours worked. We should really find the difference in hours worked for softare engineers, of course.
> The average hours worked in France is 1500, UK 1600 and USA 1800[1]. Therefore if you factor in hours worked, a developer in France should be paid 83% of average salary in America and 94% of average salary in the United Kingdom. This of course assumes that everything else is equal (which is untrue).
Notably, the longer hours worked in the US compared to Europe comes at the expense of less per-hour productivity in most studies I've seen, though not enough to result in less per-worker productivity. If that's true within Europe as well, the value of the time worked would be closer than the number of hours would suggest.
EDIT: @nawitus:
Sorry but your data is totally useless for this purpose. 1) it's the whole economy, not just programmers and 2) it includes part time workers! To imply that full-time programmers in London are working on average less than a 40 hour week is so far from reality.