I was very fortunate indeed. … For my birthday in 2018, my wife bought me two books about the tramways of Nice. Both of these books are written in French by Jose Banuado and published by Les Editions du Cabri. 
I am enjoying reading the first of the two volumes at the moment which covers the history of the tramways in Nice. I have had some conversations of a number of forums about the TNL which ran the tramways along the coast and in the city of Nice as well as a number of lines which travelled up into the hilly countryside behind the coast.
One particular area of discussion has been a practice which seems unique to Nice among other major cities in France and possibly much wider afield. The TNL ran not only passenger services but good services as well.
Sadly the story of these activities is apparently currently only available in Jose Banuado’s books which are written in French.
I have used Google Translate to translate the pages of Jose Banuado’s book which relate to the goods traffic on the TNL network. 
By 1903, the TNL was at responsible for a 94.3 kilometre network of over 90 kilometres, of which 29km were the urban lines in Nice. The network was operated with 106 powered trams, 32 trailers, 3 tractors (shunting locos) and 22 wagons for the transport of goods.
The increase in traffic required improvements to the rolling stock. “On the urban lines, the original powered vehicles saw extended platforms, and trailers were added on the most loaded services. … New powered vehicles were ordered for the coastal lines: forty vehicles which were more powerful and comfortable were delivered in two batches between 1904 and 1909. They were equipped with air-brakes and coupled permanently into pairs.“
Banuado continues: “The transport of goods took off remarkably. This distinguishes the TNL network from its counterparts in most other major French cities. In addition to postal and retail freight traffic on the coast, the Contes cement plant provided substantial tonnages with coal deliveries for its kilns and lime shipments and cement in sacks. But to ensure the best trade, it was necessary to link trams to the other major transport infrastructure of the city of Nice: the commercial port, the PLM station and the Chemin de Fer du Sud.”
As the PLM had done nothing to connect to the Port, Nice made use of trams to make the connection between the PLM station and the Chemins de Fer du Sud station and the port. An agreement was signed on 7th February 1905, which provided for some minor alterations to the tram network, “the construction of an exchange platform in the sidings of the Chemin de Fer du Sud Station and the electrification of the tracks. This meant that the TNL locomotives could access these sidings. At the other end of the city, the Chamber of Commerce, … took charge of laying tracks on the docks.”
The TNL assigned shunters/power cars and a hundred wagons to the traffic, while the Chemin de Fer du Sud de la France ordered two hundred wagons able to run on the tracks of the trams to the port of Nice and the operation commenced in 1907 after all legal issues had been discussed and agreed.
Banaudo says: “The connection to the port of Nice enabled the transport of large volumes of goods, the majority of which concerned the industries alongside the line to Contes (the Contes cement factory, L’Ariane flour mill and the Nice-Riquier gasworks), as well as exchanges with the Chemin de Fer du Sud de la France Station.” The latter provided a route to the PLM. Although the PLM had always refused a direct connection with the trams, it was connected with the Chemin de Fer du Sud Station from 1899 onwards via a short branch-line which linked the two stations, set into the road pavement of the Rue de Falicon (today, the Rue des Combattants en Afrique du Nord). So, ultimately, it became possible to transship goods from a wagon of standard-gauge to a vehicle of the TNL and vice versa.
- Nice au fil du Tram Volume 1 and 2, Jose Banuado; Les Editions du Cabri.
- Nice au fil du Tram Volume 1; p50-52.