When in October 1805 French troops again moved in during the War of the Third Coalition, Ferdinand, like his predecessor Archbishop Colloredo, had to leave his residence for his brother's court in Vienna.
Kui Prantsuse väed oktoobris 1805 Kolmanda koalitsiooni sõja ajal taas sisenesid, pidi Ferdinand, nagu tema eelkäija peapiiskop Colloredogi, vahetama oma residentsi oma venna õukonna vastu Viinis.