The woman now has asylum and lives in Berlin with her children. Her husband, who lives elsewhere in Germany but has stalked her on the street in Berlin at least once, is under a restraining order. But she remains too terrified to provide even her first name, for fear of being killed by him or another relative over the perception that she brought “dishonor” to the family.

Ms. Höhne says the woman displays all the symptoms of post-traumatic stress disorder, including flashbacks, insomnia and trouble concentrating. “One moment she will seem perfectly healthy, the next she is in her chair opposite you dodging bullets in Damascus or reliving her abuse in Bulgaria,” she said.

In Greece, one of the main entry points to Europe for migrants, reception centers are often overcrowded and lack adequate lighting and separate spaces for single women, said William Spindler of the United Nations refugee agency. “Men, women and children sleep in the same areas,” he said. Across Europe, he added, “cases of sexual violence and family violence have been reported to our staff in the field.”

Even in the relative safety of Germany, an asylum system struggling with the logistics of accommodating close to one million migrants in 2015 has been cutting corners when it comes to basic protections for women, like lockable bedrooms.

“The priority has been to avoid homelessness,” said Ms. Rabe, the German expert on gender-based violence. “But an environment that inadvertently facilitates violence is a risk factor. We cannot allow standards to slip.”

That is easier said than done, said Jan Schebaum, who manages two homes for asylum seekers in east Berlin. There are two bathrooms per floor, and the rooms are full.

Image Esraa al-Horani, from Syria, at a refugee shelter in Berlin in November. She still sleeps in her clothes and, like several women at the shelter, pushes a cupboard in front of her door at night. Credit... Djamila Grossman for The New York Times

One of the homes he runs is the emergency shelter where Ms. Horani, the makeup artist, stays. Of 120 adults there, most are Syrian and Afghan, and 80 are men.