Are there Easter Markets in Belgium where you can buy decorated eggs?
It's best to post one time in one forum. Duplicated post mess things up and are typically removed.
Suggest you pick one place and re-post there (since you have the same question about 3 countries, 'General Europe' would be appropriate).
The chocolate shops are selling Eastern eggs and bunnies in all kinds of colourful wrappings but no idea about markets with traditional decorated i.e. painted eggs.