  Trying to connect a fundamentally non-commutative spacetime with the
conservative perturbative approach to quantum gravity, we are led to the
natural question: are non-commutative geometrical effects already present in
the regime where perturbative quantum gravity provides a predictive framework?
Moreover, is it necessary to introduce non-commutativity by hand, or does it
arise through quantum-gravitational effects? We show that the first question
can be answered in the affirmative, and the second one in the negative:
perturbative quantum gravity predicts non-commutativity at the Planck scale,
once one clarifies the structure of observables in the quantum theory.
