French sprinter Emmanuel Biron was third in 6.68secs.
Earlier in the heats, Collins ran 6.59secs to win his qualifying round race, a time which was the fastest of the preliminaries.
The women’s race went to Great Britain’s Anyika Onuora, who ran 7.33 seconds to edge Celine Distel-Bonnet of France.
The other highlight at the meeting came in the men’s pole vault, which saw Olympic champion Renaud Lavillenie of France capturing his eighth successive victory, while improving on his world-leading mark with a winning clearance of 5.94m.
Lavillenie cleared 5.60m, 5.76m and 5.80m before clearing his winning height – all on his first attempt.
He took three tries at 6.00m, but missed them all.