> they later realised their mistake

Here’s the very problem. The police acting immediately to suppress a supposed threat (even “active” ones, whatever that means) which allows them to silence protest or even inconvenient questions to a public servant…

… and we’re splitting hairs here, but it also allows the police to be manipulated by said public servants to get the protest silenced on their behalf.

The police in this case should have quickly realised the individuals were journalists, posed no real threat (no weapons, explosives, chemicals on their persons) and let them go about their business.

I agree that the police could probably have acted more 'flexible' in the first few seconds before removing the journalist from the event. The other somewhat weird fact is that they showed up in 'cilivian' outfits instead of in uniform.

Yet still the *main* problem is the ambassador lying about that person being an active threat.

E.g. what if that information would have been correct? All hell would break lose if the police wouldn't take such a call serious and the supposed 'threat' would be real and people killed, from that perspective they seemed to have reacted quite civilized and calm.

If the events happened as reported, the ambassador should at the very least be summoned and grilled by the Belgian government.