The 44-year-old was discovered by a cleaner who came to work in the building, and she informed authorities, Alberto Crescenti, the head of emergency services, told the local news channel TN.
"I couldn't believe it. He was a healthy, marvelous, caring, very dear person. Tell me it's not true," cried Anama Ferreyra, a Brazilian model raised in Argentina, on the same channel.
Ibanez was a women's fashion designer whose clients included the biggest stars of local television, such as actresses Mirtha Legrand and Susana Gimenez.