Now that he’s in Glasgow, we can say that Christopher Jullien used to walk with a gallus swagger. Back in 2013, Celtic’s new £7m signing had good reason to feel quite chipper. He had just won a World Cup medal with France’s under-20s and signed his first professional contract with German club Freiburg.

That sense of cockiness swiftly evaporated, however, as a largely downbeat spell in the Black Forest city just about left his shoulders sagged at half mast. Out of darkness cometh light, however, and having made his way to Glasgow via Toulouse, Jullien looks back on those formative years, not with despair and despondency but with appreciation.

“I would say the best time of my career would be the part in Germany where I failed,” said the 26-year-old. “I think it was the best time for my career because it made me realise what I had to do to become stronger and to play. I didn’t play much there.

“It was a difficult moment and it was at that time when I realised I had to do more. I was young and I was maybe just thinking that football is easy. I went there at 20-years-old after winning the World Cup. I thought, ‘I’ve won the World Cup so everything will be fine’. “I arrived there with the wrong mind-set. I was thinking everything would just automatically be perfect.

“The bad experience taught me who counts in my life and who can help me to follow my dream. After that, I realised I had to do better.

“It was a difficult and lonely time. I was far from my home in a different country and trying to cope with a different language. It’s different circumstances now because I arrive in Scotland and I’m able to speak English.

“I think every player has to be in a bad position at one point to grow up and learn things. The time in Germany was when I learned the most.

“I still speak about it now with my dad, Pascal. He keeps the moment in his mind and will say to me that he is so sad that I lost two years of my life in Germany. I say 'no, I am happy. It was a good moment’. I realised I had to do more. It’s not the name you have or the talent you are born with, you just have to work for everything. Now I can thank Freiburg and that time for being here and being the man I am.”

Jullien’s captain in that 2013 World Cup team was Paul Pogba, who would go on to win the real thing with his country in 2018. With time on his side, Julien has not giving up hope of scaling the heights on the international scene. “I’m still thinking about it,” he said. “When I saw them (his former under-20 team-mates), the first thing I did was send them a text to say congratulations. You win the ’little’ World Cup, and now you’ve won the big one. After that text I was just like, I could have been there. For me it’s still a goal to be part of the national team. I know it’s going to be difficult but you just have to work for it and not have any limits.”