The breakdown in service, which was traced back to Orange, meant that phone users at other French networks found it difficult — or even impossible — to call Orange customers and vice versa.
So while Orange was obviously the worst hit, France's other mobile operators: Bouygues, Free and SFR were also badly affected.
The first breakdown in service hit the network at 9.50 am on Monday and was fixed by 12.20 pm but a second failure hit at 2 pm which was not fixed until Monday evening.
While some phone users were still able to make calls throughout the fault, tens of thousands weren't and many calls that did connect were of a poor quality.
Orange, which traced the problem back to their mobile interchange, had promised to “do everything to restore the networks as soon as possible”.
Internet connections were not impacted throughout the breakdown in service so calls via WhatsApp and any other web chat apps were still possible.
On Monday afternoon, France's other three major operators were considering a “total cut with the Orange network” as a way of reassuring their customers, according to Le Parisian.
So-called secondary operators including NRJ, La Poste Mobile, Virgin and Cdiscount Mobile were not been affected by the technical fault.