A very bright green insect rather like a grhopper.?

I woke up last night to hear what I thought was my cat eating her cat biscuits. However, she was asleep on the bed. Noisily crunching the cat biscuits was a large very bright green grhopper type thing, about 2-3" long. It had feelers and what looked like a feeler on its backside too. I live in the south of France. I've looked up cicadas, locusts and grhoppers but don't see anything which it resembles.