They must be very careful when talking to the French maids--not the slightest allusion to the nationality of Dona Elena's husband nor to the residence of her family.

Dona Elena was an Argentinian.

But in spite of the silence of the maids, Don Marcelo was always in fear of some outburst of exalted patriotism, and that his wife's sister might suddenly find herself confined in a concentration camp under suspicion of having dealings with the enemy.
Frau von Hartrott made his uneasiness worse.

Instead of keeping a discreet silence, she was constantly introducing discord into the home with her opinions.
During the first days of the war, she kept herself locked in her room, joining the family only when summoned to the dining room.

With tightly puckered mouth and an absent-minded air, she would then seat herself at the table, pretending not to hear Don Marcelo's verbal outpourings of enthusiasm.