Olympic 200m freestyle and 4x100m relay champion Yannick Agnel on Friday attributed his two new records to a chocolate hazelnut spread as he took the French national short-course championships by storm.

France's double gold medallist in London said an official asked him to sign drug test papers just as he got out of the pool on Friday after lowering the European 800m freestyle best by just over two seconds to 7min 29.17sec.

"I told him that I was only doped up on Nutella and he could stick that on the form," Agnel told reporters.

The 20-year-old on Thursday evening set a world record in the short course 400m freestyle of 3min 32.25sec, beating the previous mark of 3:32.77 set by Germany great Paul Biedermann in Berlin in November 2009.

Agnel is also eyeing wins in the 100m and 200m freestyle this weekend.