However having learnt to stay on the right side of referees, Maestri has become a regular for Toulouse this season, and has now been given the French starting job ahead of veteran Lionel Nallet.
But Maestri admits he cannot afford to rest on his laurels ahead of the encounter against Ireland who will be looking for only their second win in Paris in the RBS 6 Nations.
He said: "In comparison to my early years it's undeniable [that my discipline has improved]. But you always have to stay alert and be rigorous every weekend.
"It's very easy to fall back into those mistakes. There were periods when discipline was a problem. It was to do with my commitment and my will. I had a realisation to calm down.
"At Toulon and Toulouse I worked really hard with the coaches to learn to be more rigorous."
Maestri has taken longer than expected to break into the French squad but will now get his chance when he goes head to head with Ireland skipper Paul O'Connell.
And having had to wait to finally make a start for Les Bleus, the second row admits he cannot wait to take on Declan Kidney's side.
He added: "Everything happens in its own time. We get what we deserve. It wasn't a case of my age. If I wasn't there before, there was definitely a reason for it. I just tried to be as good as I could for my club.
"I've had a lot of work to do, that takes time. But I say to myself, now finally, I will be out there.
"I'm not someone who is likely to get carried away. We are expecting a very tough match. I don't want to get distracted by the occasion. We are well aware of what is waiting for us."