The signs say “I Am a Man,” but the new mural at 14th and T streets NW might make you contemplate what it means to be a Washingtonian, an American or a human. After two days of gluing from precarious three-story scaffolding, the French street artist JR completed his first D.C. installation: a building draped in Ernest Withers’s iconic civil-rights-era photo of the 1968 Memphis sanitation workers strike.

“This says it all, ‘I am a man,’ ” said JR, referencing the signs the pickets are holding in the photo. “They created such a strong and powerful image that still resonates today, but in another context. Still people say, ‘I am a man,’ but they care less about the color [of their skin]. It’s ‘we are humans, we are here, we want to exist.’ And I like that, I think that’s pretty powerful.”

The building-size installation had already captured the attention of passersby. As construction cranes for the nearby Louis apartment project pivoted above and flecks of glue rained down below, a small crowd gathered to take photos. Photographer Steven Cummings lamented a wasted opportunity: Earlier, a garbage truck had pulled in front of the mural of the striking sanitation workers, “but I missed the photo,” he said.

Minutes later, another garbage truck pulled up, and Cummings dashed across the street, camera in hand, taking care not to step in the pools of milky paste that had gathered near the gutters.

JR won the $100,000 TED prize in 2011 for his pledge to “use art to turn the world inside out.” He glues massive black-and-white photographs onto buildings around the world but — with the exception of some murals in Los Angeles and at the High Line in New York — rarely works in the United States. He prints his photos in strips on the large-format printers used for architectural blueprints and pieces them together on-site. This mural was installed with the permission of the unoccupied building’s owner, designer and art patron Lori Graham, on the south facade of 1401 T St. NW and was facilitated by Lauren Gentile, director of the Contemporary Wing gallery.

Even though the image wasn’t from Washington, JR said he felt that it spoke to the history of the neighborhood after the riots that followed the Rev. Martin Luther King Jr.’s assassination and to the state of American society now.

“I’m not pushing for an interpretation,” he said. “I’m sure the people here, because of their own stories and their own frame of reference, would actually relate in a much more interesting way. . . . I’ve always been so surprised by how people interpret my photos in context.”

There’s no telling how long the mural will last.

“It depends on the weather — it might stay for years, it might stay a couple of months,” JR said. “It might peel in a few places. I like that, too. I should never impose an image forever. I like how ephemeral it can be.”

Rose Jaffe, a 23-year-old artist and fan of JR’s work, stopped by with a photographer friend and her 5-month-old Labrador retriever to watch the mural in action. When she introduced herself to the artist, she was told, “Grab a brush.” She helped JR and his team of five assistants affix the mural to the building.

“This is like a globally famous street artist,” she said. “It’s incredible that I get to hold the same brush as him.”

Indeed, meeting the neighbors has been the best part of the mural installation, JR said.

“When you’re in New York, people don’t say, ‘We’re happy you came to New York.’ In D.C., people thank you for coming here and bringing art here,” he said.