Emel Mathlouthi at the French Institute's Tunisia Festival Emel Mathlouthi The Tunisian musician performed at the French Institute Alliance Française on Wednesday for its World Nomads Tunisia festival. The Tunisian singer Emel Mathlouthi, a gentle firebrand whose song "Kelmti Horra" ("My Word Is Free") became an anthem of the Arab Spring, made an enthralling New York debut at the French Institute Alliance Française on Wednesday night. In Arabic she sang, "We are free men who are not afraid/We are the secrets that never die/And we are the voice of those who resist." The song has a forthright, steadily rising melody in a major key; it's easy to imagine it being sung by Joan Baez, one of Ms. Mathlouthi's early role models. On Wednesday she began it quietly, almost like a lullaby, and carried it toward a clarion fervor, moving between Western and Arabic modes and drawing the audience into a singalong finale. Ms. Mathlouthi is a 21st-century performer, versed in Western rock and dance music and touching on styles around the Mediterranean. Her 2012 international debut album, "Kelmti Horra" (World Village/Harmonia Mundi), uses rock and Middle Eastern instruments, electronics and samples of protests and speeches from the Arab Spring. On Wednesday she had only half of her usual Tunisian band, a keyboardist (mostly on piano) and a guitarist who could play oudlike lines. These musicians summoned the momentum of flamenco or created eerie electric-guitar drones and effects. Her percussionist and violinist could not get visas. She performed barefoot, sometimes using pedals to add effects to her voice or make loops of her vocals and guitar. Ms. Mathlouthi, 31, grew up in Tunisia listening to Western rock and to the 1960s folk revival, drawn to its spirit of protest. She went on to discover socially conscious Arabic-speaking songwriters like Sheikh Imam, from Egypt, and Marcel Khalife, from Lebanon. She opened the concert singing Mr. Khalife's "Bghalbetek" solo, with electronic echoes of her voice. Ms. Mathlouthi wrote songs of her own about Tunisia, but they were banned and her career was stymied. In 2007 she moved to France, where a friend, Amin El Ghozzi, gave her the lyrics for "My Word Is Free." Ms. Mathlouthi writes both words and music for most of her songs. A video of "My Word Is Free" from a Paris concert spread, via YouTube and Facebook, around the Arabic-speaking world. She was on tour in Tunisia when the revolution arose in 2010, and in another widely circulated video she performed "My Word Is Free" during a rally there. Her concert offered resolve and compassion, not stridency. She introduced songs in English: a homage to "people who fought for our freedom," a song against fear, a song called "Dhalem" ("Tyrant") that vowed, "Kill me, and I will write songs." Each one was a musical narrative, unfolding in multiple sections, moving between delicacy and fierce tenacity, mourning and defiance. And her serious sense of purpose didn't stop Ms. Mathlouthi from dancing at the end, twirling barefoot.