A radar echo is an electronic signal that contains information about the location and distance of the object which bounces the signal back.
According to the French statement, the debris was floating around 2,300km from Perth.
It said France would increase its satellite capacity to continue the search in the zone.
Earlier, the Transport Ministry said in a statement that French satellites had detected 'potential objects in the vicinity of the southern corridor', and have sent the images to Malaysia.
The information was relayed to Malaysia Sunday morning, and the images were immediately relayed to the Australian rescue co-ordination centre.