[3] In 1917 / 1918, with consent of Charles I, Maximilian established his household at Belvedere Palace in Vienna, held to the disposition of the imperial family by the government of Austria.

[6][8] As Charles I, not anymore participating in state affairs since November 12, 1918, still considered himself emperor, this suggestion did not conform to the family rules of the dynasty.

On 3 April 1919, the Constitutional National Assembly elected in February passed the Habsburg Law which stipulated members of the former ruling family could only live in Austria if they cancelled their membership to the Habsburg Dynasty with its monarchial aspirations and if they declared themselves loyal citizens of the republic.

Maximilian Eugen and his family in 1919 were given permission to live in Switzerland on condition that he did not engage in political activity.

[2] In April 1922 Maximilian attended the funeral of his brother Charles in Funchal, Madeira,[9] after which Zita and her children returned to mainland Europe.

In June 1923 Maximilian sued his late brother's secretary Baron von Steiner for fraud in the sale of some family jewels.

[10] In November 1930 Maximilian attended the ceremony in Ham, Belgium commemorating the coming-of-age of his nephew Otto, from then onwards until 1 January 2007 chief of the House of Habsburg-Lorraine.