Presuming for the moment NOD's assertion that the possible call at NCE was for fuel, does he then go on to assert that said aircraft would then depart with one engine inop, enroute to CDG...with passengers?
Of course not...
However, the general point I was making is that for the 2 airlines I have worked for (VS, BA), a single engine failure, secured, with no further problem is not an "emergency". No need to land...
Of course, there now needs to be a plan, allowing for a possible second engine failure (a problem eastbound Transatlantic say) with associated fuel consumption and ceiling considerations. Depending on circs, this may be return to Departure A/F, call in at one en-route (and as you say, this means all PAX off and engine fixed or 3 engine ferry onwards), or continue to destination. A commerical bonus is if you can get say 75%+ of the way home, then the "spare" aircraft can be waiting at the intermediate stop to take the PAX onward, and even have brought out the 3 engine ferry crew...
It might have been different in your 707 days 411A, but seems SOP now for modern 4 jets (744, 340)...