2001 Peugeot 307 1.6 16v passenger door problem.

[Agile]

The passenger door will not unlock, as far as I can guess, based on the feel of the handles.

This is annoying but even more so when you really need the door to open to actually inspect the lock mechanism.

Any suggestions as to what the actual problem might be?

Or ay suggestions how to get it unlocked to inspect it?