Where to find freelance work?

I gather the tag "developer" suggests you want to work in IT, and you are already an established freelancer with a legal company type structure in place.
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Direct freelance jobs are all word of mouth.
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It it's advertised, then it's either permie, or through an agency. Usually both.
Be vary wary of "direct" freelance jobs that don't come through people you know, especially for small companies. They are almost always dodgy, either on the legal front, or they are financially unsound.

www.jellow.be is an online matching platform which connects freelancers and employers directly, without intermediairies. Freelancers register for free, employers pay a monthly subscription.