The three properties are located in on Rome's Janiculum hill and the nearby upscale Monteverde neighbourhood, according to police.
A villa and an apartment bloc, a shop and agricultural land in the Calabrian coastal city of Palmi were also impounded in Wednesday's operation.
The operation followed probes by anti-mafia prosecutors that led to the police on 12 November of the four-star Grand Hotel del Gianicolo on the Janiculum hill, which is famed for its views of the city.
Anti-mafia police also seized two other four-star hotels in Rome and a four-star hotel in Palmi as part of the November operation.
In a separate operation on Wednesday, Italian tax police seized a tourist development worth 200 million euros in the Calabrian coastal town of Brancaleone after a probe by Reggio Calabria anti-mafia prosecutors.
Five people are under investigation in the probe, two of whom are under house arrest. The suspects face charges that include fraud and violation of building regulations in a natural beauty spot.