Madonna's Rebel Heart tour has taken her to Paris, where the star is paying tribute to those lost in the November 13 terrorist attacks.

The singer held an impromptu concert in Place de la Republique—the site where the French held public demonstrations and mournings after its two terrorist attacks this year—for a small crowd. Dressed in just a jacket and accompanied by a guitarist, Madonna sang her songs "Like a Prayer," "Ghosttown" and a cover of John Lennon's "Imagine" (above) that had the whole crowd singing along.

According to France 24, the singer spoke about the city in her concert earlier in the night. "I think of what happened almost four weeks ago now, the heart of Paris and the heart of France beats in the heart of each city. We are one heart and our heart can beat as one...the power of love is greater than the love of power...I came here when I was 20 and it was here, in Paris, that I decided to make music. Thank you Paris for planting that seed in my heart!"

Click here to understand why "Imagine" stands the test of time whenever the world is troubled.