Exchanging sexual services or performances for material compensation is a lucrative business, globally. Punishable in some parts of the world, prostitution is decriminalized and regulated in Mexico. The women who submit to this lifestyle come from various walks of life: young mothers, runaways, brave survivors and trafficked persons. They routinely, daily and hourly commit sexual acts, having intercourse with as many as several dozen men a day. They're also vulnerable to abuse, violation and disease. But, after a lifetime of performing this role, what happens to women when they age out of prostitution? Photographer Bénédicte Desrus spent six years at home in Mexico City, which houses women who've spent their lives in sex work, answering that question while documenting the women of Casa Xochiquetzal.

Carmen Munoz, a retired sex worker, opened Casa Xochiquetzal in 2006. The erection of the new shelter drew Desrus to Mexico City, as Desrus was tasked to photograph Munoz for a magazine. Upon arriving there, Desrus discovered the 26 women who lived there and became fascinated with them and their lives. She built slow-approach, organic relationships with the women, using humor and curiosity to elicit their stories. She visited often and observed, taking portraits of women who wanted to be photographed, and simply listened to the stories that were being told to her.

Desrus learned the story of María Isabel, who ran away at 9 years old because she was being "used" by her father; she turned to prostitution at 17 when her caretaker, a woman who discovered her at a bus station, died. Canela, 72, a well-known and respected woman in the area, suffered from Down syndrome and a number of other illnesses. Leticia was abandoned by her mother at the age of 8, and turned to sex work after her abusive husband began to bring women to her home. She left behind her marriage and children, twice attempted suicide, and now is Casa Xochiquetzal's resident "peacekeeper." Norma was abused by her brother's friend and a priest before she turned to waitressing in the red-light district.

Beyond learning about the lives of the women at the shelter, Desrus also learned about deaths and disappearances at Casa Xochiquetzal. Paola was the youngest woman at the shelter and was still working the streets when she disappeared from the shelter on Jan. 1. 2011; she has yet to come back. In 2010, a resident and retired sex worker died of cancer at age 64, and Desrus documented another sex worker paying respect.

Later, Desrus teamed up with journalist Celia Gómez Ramos, who interviewed and transcribed the stories of the residents, developing a non-patronizing or glorifying book, "Las Amorosas Más Bravas" ("The Toughest Lovers"). Together, the two women recorded experiences from some of the 250 women from ages 55-86, who'd received help from the shelter since it opened in 2006.

Munoz worked for 20 years to persuade the government and NGOs to open the establishment. Mexico City's municipal government provided the building and the resources that guaranteed women access to shelter, healthcare and food. In the communal home that the "territorial" women share, they participate in daily maintenance of the home and learn to support one another as survivors and strong women. The women at the shelter are more fortunate than most, and many know it. Others who have "aged out" of prostitution become homeless, hopeless and lost. Many are diseased and die alone with nothing, which is why facilities like Casa Xochiquetzal are so necessary.

To learn more about Casa Xochiquetzal, visit the home's Facebook page. To see the work of Mexico City-based, French photographer Bénédicte Desrus, visit her on Facebook or Twitter.