Wayne Pivac was unimpressed with the officiating after Wales suffered a narrow defeat to France that leaves the defending champions with only a slim chance of retaining their Six Nations title.
Romain Ntamack was the star of the show as Les Bleus ended a 10-year wait for a victory in Cardiff, winning a thriller 27-23 on Saturday.
Ntamack scored 17 points in a fly-half masterclass at the Principality Stadium for a France side that have won three out of three this year, putting them on track for a first Six Nations crown in a decade.
However, Wales felt they should have been awarded a penalty try by referee Matthew Carley for what they saw as a deliberate knock-on by Paul Willemse when Ken Owens attempted to set up Josh Adams in the second half.
Head coach Pivac said: "We have had a look at the slap down and I think the officials may have got that one wrong.
"That killed momentum as well."
Pivac was also aggrieved when France were awarded a penalty in a scrum as Wales applied the pressure, with prop Wyn Jones having stated this week he expected Les Bleus to "cheat" when they packed down.
"Another disappointing moment was when the French tighthead [Demba Bamba] came on and went straight across the scrum and was rewarded for that," said the New Zealander.
"Those were the big moments in the game. The scrums, from our point of view, had gone okay up until that point.
"You have got to go with the forward motion but he clearly went across the scrum."
Pivac said wings George North and Adams will be checked over after suffering head and ankle injuries respectively, with Wales having games against England and Scotland in March.
"George will go through the normal protocols for a HIA [head injury assessment]. He was taken off the field for a HIA," Pivac stated.
"Josh Adams had an ankle injury. We will have to check him in the next day or two to see how severe it is."