The 19-year-old Sao Paulo star looked set to join the Red Devils earlier this week only for PSG to intervene at a late stage in the talks.
The Brazilian’s agent, Wagner Ribeiro, has explained that the role of PSG sporting director Leonardo was significant in persuading Moura to move to the free-spending Ligue 1 side.
“Everything was agreed between Sao Paulo and Manchester United,” Ribeiro told UOL.
“The contract had been written (and) just needed to be signed. But then Leonardo called me and asked to talk to Lucas.
“They talked. Leonardo was helped by the fact he is Brazilian. He was very gentle with Lucas.
“The possibility of living in Paris – a much more pleasant city than Manchester – also influenced his decision. But it was PSG’s project that impressed Lucas.”
It represents a remarkable turnaround as United boss Sir Alex Ferguson appeared to have got his man, and Ribeiro has detailed his own hectic role in the negotiations.
“I’m just a worker,” he added. “I’ve not been able to sleep for five days here in Europe. I can’t rest and I miss my son.
“I boarded a plane at 5am in Manchester and arrived in Paris this morning to finalise everything with Leonardo.
“But what gives me the taste of victory is that I know Lucas is happy.”