In a live TV address to the nation, a shocked French president François Hollande said "This is a tragedy on our soil."
He dampened any hope from the outset by announcing that the site of the crash was "a very difficult area to access", and added that there were not expected to be any survivors.
Later, speaking on BFM TV, French Interior Ministry spokesman Pierre-Henry Brandet said debris was found at an altitude of around 2,000 metres (6,500ft), and that the remoteness of the area meant "an extremely long and difficult" search operation was to be expected.
Mr Hollande confirmed that there were likely to be a number of German nationals on board the flight, and that he would be speaking shortly with the German chancellor, Angela Merkel.
Commenting on the disaster, Mrs Merkel said that she was deeply shaken by the tragedy and that her thoughts were "with those people who so suddenly lost their lives, among them many compatriots".
She also said that she will travel to the region today, a day after her foreign and transport ministers were heading to the crash site.
She said "that this is the hour of our pain". She also urged people not to speculate on the cause of the crash until an investigation can be conducted.
Spain's King Felipe has cancelled his state visit to France following the crash in the southern French Alps.
Felipe met with Mr Hollande yesterday.
The plane was flying from Barcelona to Duesseldorf in Germany, and Spanish deputy prime minister Soraya Saenz de Santamaria told reporters in Seville that there were 45 people aboard the plane with Spanish last names but that authorities have not confirmed how many of them were Spanish.