Harinordoquy believes he fell well below his best in last weekend's 23-17 Sux Nations victory at Murrayfield.
And the mighty Biarritz number eight, one of France's star performers during their march to last autumn's World Cup final, has braced Ireland for the backlash.
"I can and almost certainly must play better," said the 32-year-old.
"In the first half in particular I had the impression that I spent most of the time defending.
"With regard to defending I was active whereas in offence I was too passive. In the second-half it was a little better."
France misfired at the line-out against Scotland and Harinordoquy has pointed the finger of blame at himself.
The line-out is an area of Irish strength and Les Bleus, who have dispatched Italy and Scotland so far in this Six Nations, can ill-afford another bad day at the office.
"I take responsibility for that because I was captain of the lineout," he said.
"I was too focused on the patterns and calls we had made during the week leading up to the match.
"I was unable to adapt when they played a different pattern at some line-outs. We came under a lot of pressure in this area.
"We had already done a lot of work on their line-out habits in the lead-up to the original game before it was postponed.
"But perhaps it is best to leave it more to intuition on the day."
Victory over Ireland would keep France on course for a Grand Slam decider against Wales on May 17, but Harinordoquy insists improvement is essential against Ireland for that to happen.
"Offensively we were all over the place against Scotland, launching solo attacks without taking into account a more orderly approach to counter-attacking," he said.
"We were a bit disorganised. The players, including myself, sometimes took too long to follow the man with the ball and provide some impetus behind him. It's imperative we correct that."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.