Mr Lyon, from Longwy, north-eastern France, had travelled to Nice with his wife Veronique, 55, son Michael Pellegrini, 28, and in-laws Francois Locatelli, 82, and Christiane Locatelli, 78 for an eagerly anticipated holiday on the Riviera. His parents Gisele Lyon, 63, and Germain Lyon, 68, also joined the family gathering.
Michael, Christophe's son from a previous relationship, taught economics at a local sixth-form college. A colleague of Michael said he was "overjoyed" to be attending the Bastille Day fireworks display.
Mr Lyon's elderly parents and in-laws were enjoying their retired life and had been looking forward to a family holiday. Germain and Gisele, who were recently retired had taken an extended trip to the Côte d'Azur, spending several days in Marseille before joining their family in Nice Mirro Online reports.
All six died as they were struck by the truck which was driven at high speed for over 100 meters, 'zig-zagging' between the crowd to maximize injury. The truck was "riddled with bullets" as the driver was "neutralized" by police.
At least 84 people were killed in the massacre, among them 10 children, with another 202 were injured – 52 of them seriously. Fifty children were said to have been taken to hospital with some of their relatives still not found.
Islamic State (Isis) claimed responsibility for the truck attack, as French police arrested five people in connection with the massacre.
France has begun three days of mourning as the investigation into the attack that devastated countless lives continues.