UPDATE #2: A black box has reportedly been found: 

BREAKING: French interior minister: A black box has been found at plane crash site in French Alps.

— The Associated Press (@AP) March 24, 2015

In addition, this image appears to show the crash site. 

Photo shared by @laprovence appears to show the crash site of Flight 4U 9525 in French Alps pic.twitter.com/QqeD2q0AiX

— BuzzFeed News (@BuzzFeedNews) March 24, 2015

UPDATE: According to the Associated Press, French Prime Minister Manuel Valls said that a helicopter landed near the site of the crash, but was unable to locate any survivors. In addition, a local official  said that the plane had been completely destroyed: 

Gilbert Sauvan, of the local council, told Les Echos newspaper, The plane is disintegrated.

The largest debris is the size of a car, he added.

French officials say a plane with at least 148 passengers crashed in France today. Worse, all aboard are feared to have perished. 

According to CNN, French Prime Minister Manuel Valls said the Germanwings Airbus A320 crashed in southeastern France's Alps de Haute Provence area around 10:30 a.m. Furthermore, Valls noted that the 142 passengers and six crew members aboard could have been killed. French President Francois Hollande told CNN that, while the specifics of the crash are unknown at the moment, authorities have reason to believe "there will be no survivors."

CNN reports that the plane was traveling from Barcelona, Spain en route to Dusseldorf, Germany. CNN adds that a police helicopter had arrived to the scene of the crash.

[via CNN]