Sending money abroad - what are roughly the limits for what I can send without beeing reported to Belgian authorities?

If I send money abroad, what are roughly the limits for what I can send without beeing reported to Belgian authorities?  (If I want privacy, or have something to hide :-).

Is bank transfer and Western Union about the same?
Does it depend on nationality of sender?  Receiving country?

(I know Belgium has bank secrecy, though not as strict as Luxembourg, and that for ingoing transfers scrutiny  is in principle only for anti money-laundring anti anti-terrorism)