They're building the partitions for the Cardinals in preparation for the conclave. Leoni and Rinaldi walk by conversing. Somebody drops some electrical equipment in Leoni's hands and says "Hold the lamp." Then he climbs off the ladder and says "Give me the lamp." Then he's embarrassed that he has incovenienced a Cardinal and starts whispering, looking for "Franco!"
I know exactly who you mean, in fact, I came to look it up after watching a DVRed recording of the film. I thought he looked like Stanley Adams although I know it isn't that actor. I do know that I've seen this man before in comic roles in international films.
I'll have to transfer the recording to a disc and make a screen capture to perhaps jog some memories around here and get an answer for both of us.
It ain't easy being green, or anything else, other than to be me
Bert Kwouk, an English actor of Chinese descent played Chairman Peng in this. He was later known as Clouseau's maniac valet in the Pink Panther films.
In his old age he played "Electrical Entwhistle", an electrician & washing machine salesman in the long running English TV serial "Last of the Summer Wine."