The NYT has an article telling readers that Latvian officials working for the European Union bureaucracy earn much higher pay than their counterparts who remain in Latvia. This is of course true. It would be very surprising if it were not the case.
The European Union is dominated by relatively wealthy countries like France, Germany, and the U.K. It would be expected that the pay of its officials would reflect pay scales in these countries. This means that when poorer countries, like Latvia, enter the EU, their nationals can anticipate big pay increases if they move from employment by the Latvian government to employment by the EU, just as a plumber would get a big increase in pay if they moved from Latvia to Germany.