Muladuzi was third coming off the final bend, and while he got past Kenya's Richard Kiplagat as they hit the straight, 21-year-old Abubaker Kaki of Sudan was well clear as he coasted away to victory.
Kaki, the world indoor champion, clocked 1:43.50 to settle in third place in the 800m Diamond League season race, while the veteran South African finished in 1:44.11 and now has eight points - still four points behind Rudisha who did not compete in Paris.
The only other South African athlete in action, Rene Kalmer, will be pleased with her first outdoor performance over 5 000m this season, despite trailing well behind a world class field.
Kalmer was 15th in 15:44.08, falling less than 10 seconds short of her personal best, in a race won by Kenyan world champion Vivian Cheruiyot in a meeting record 14:27.41.
David Oliver of the US threatened Cuban Dayron Robles' world record in the 110m hurdles.
Oliver won easily in 12.89 seconds, only two hundredths of a second shy of the 12.87 world best set in Ostrava in 2008.
Sprint world record holder Usain Bolt of Jamaica won a much-anticipated clash with countryman Asafa Powell in the men's 100m race.
Bolt took victory in 9.84 seconds, also a new meeting record, with Powell clocking 9.91 for second place.
The next Diamond League meeting will be held in Monaco next Thursday.