Chris Ashton has grabbed all the headlines for equalling the Six Nations' try-scoring record -jointly held by Will Greenwood and Shane Williams - with six scores in just two matches.
But Yorkshireman Ellis, who has now been working with France for a decade, is confident if France can cut off his supply by targeting Flood.
"Toby Flood always has been a very good player but he has emerged this season as a class No.10 at international level," Ellis told the Daily Mirror.
"He is dictating things and he is creating things and he is causing a lot of problems for teams.
"Chris is a good finisher without doubt but if you concentrate too hard on one particular person it takes your focus away from everything else.
"If we can achieve that then we stop any threat that Chris Ashton poses.
"We're quite confident. We've got some interesting things waiting for them.
"I'm quite happy that there's a few holes for people to look at because those holes won't be there on Saturday week I can guarantee that."