Brussels is more expensive than the rest of Belgium, but generally the salaries should match. 3300 euro before tax is the average Belgian salary. This is only about 2070 euro after tax for single people - way too low. So salary should be quite a bit higher in Brussels, especially for software engineers, and especially in these market conditions (demand has never been higher). It depends on your education (master/phd degrees are more respected in Belgium), on your quality of previous experience, and most of all on your ability to sell yourself. Probably around 4K is more appropriate.