Question juridique clé
Whether the tenant could rely on the 1998 housing-office letter as a protected assurance under the principle of good faith.
Solution extraite
The letter did not amount to a binding assurance that the tenant could keep the apartment indefinitely; the reservation of a significant change was broad enough to cover more than a change only in the tenant's personal situation.
Motifs extraits
Under the objective principle of trust, the tenant had to understand that the exceptional permission was provisional. The wording excluded any definitive entitlement and could not reasonably be read as creating an acquired right to remain for life.