Rugby World Cup 2015: England pay for 'shocking' discipline
Captain Chris Robshaw blamed England's "shocking" first-half discipline for their 25-20 defeat by France in Paris.
Head coach Stuart Lancaster's World Cup preparations suffered a blow as for the first 70 minutes a largely first-choice XV struggled to deal with French power.
Two late tries flattered the visitors, who have one game left before launching their World Cup campaign against Fiji on 18 September.
"We gave away penalties and our discipline was shocking," said Robshaw.
"Whether it was rust, or nerves, it wasn't good enough. Credit to France, they put us under pressure and made us make mistakes.
"We gave too many penalties away, but in the second half we came out and played well but couldn't quite get over the line in the end," he told Sky Sports. "We can't give teams like France and other quality sides head starts like we did.
"We'll look long and hard at ourselves, because we let ourselves down in the first half. We played well in phases but you can't wait for 40 minutes to do that."
What did Stuart Lancaster think?
Late tries from Danny Cipriani and Jonathan Joseph made it close on the scoreboard but Lancaster was left with much to ponder by a disappointing team display in the Stade de France.
The head coach, who must announce his final squad by 31 August, added: "We've got to get our discipline at the breakdown - we can't give France easy position like we did. We need to improve on that, because all the little mistakes add up.
"The bench made a difference. It upped the energy levels and we scored some good tries. I won't gloss over what went on before that, because it was too little too late.
"There are a few players who have given me food for thought, those guys who came on and gave us the energy we needed and made a difference.
"I need to have a sleep on this game and think about my final squad. We're two weeks away from playing Ireland and four weeks away from Fiji in the World Cup and we'll expect a reaction next time."
We need to make amends against Ireland - George Ford
England host Ireland in their final World Cup warm-up game at Twickenham on 5 September.
Fly-half Ford told Sky Sports: "I thought we might snatch that at the end but we had hardly any ball in the first half and gave away too many penalties. We played some good stuff in the second-half.
"In the first half a lot of our undoing was down to ourselves. We just weren't good enough in that first half and there's no excuse for that. We let them build up the score and that made it hard for us.
"It was frustrating and we had to think of ways to adapt and that was constantly going through our minds. We tried to get ourselves out of a hole.
"We've got to turn up against Ireland now and make sure that we win. Our basics have got to be world class."