  Investigations of possible violations of the Pauli Exclusion Principle
represent critical tests of the microscopic space-time structure and
properties. Space-time non-commutativity provides a class of universality for
several Quantum Gravity models. In this context the VIP-2 Lead experiment sets
the strongest bounds, searching for Pauli Exclusion Principle violating
atomic-transitions in lead, excluding the $\theta$-Poincar\'e Non Commutative
Quantum Gravity models far above the Planck scale for non-vanishing
$\theta_{\mu \nu}$ ``electric-like'' components, and up to $6.9 \cdot 10^{-2}$
Planck scales if $\theta_{0i} = 0$.
