The incident occurred shortly before Shelvey scored the home side's third goal in their 3-0 win over the Magpies at the Liberty Stadium.
The former Liverpool player exchanged words with Debuchy and, as they took part in a heated stand-off, Shelvey appeared to motion his head towards the Frenchman's, although he did not appear to make contact.
As such, it is believed the incident does not constitute violent conduct and with referee Howard Webb on the scene as the incident unfolded, Shelvey will not face retrospective action.
Speaking following Wednesday's game, when asked if he had headbutted Debuchy, Shelvey told BT Sport: "That's what you think. Nowadays you can't do anything.
"I was trying to move to get out of the way. That's life at the end of the day."
Last month the 21-year-old was "reminded of his responsibilities" by the FA for a gesture he made towards Cardiff fans following Swansea's south Wales derby defeat.
But Newcastle manager Alan Pardew felt Shelvey should have been dismissed by referee Webb.
He said: "Looking at video highlights I think that was disappointing from Jonjo as I think he is a terrific lad and that's unlike him, but again maybe you could argue he should not be on the pitch."
However, Swans boss Michael Laudrup unsurprisingly had a different take on the incident.
"Football is about temperament. The most important thing is to keep on the right side of the line, to not go over it and he didn't do that," he said.
"It's important everybody sticks to the right side of the line."
The incident with Debuchy marred an otherwise excellent display from the England Under-21 international who, after a patchy start to life in south Wales, has turned in a string of strong performances of late in a deep-lying role.
If he can continue his form, Shelvey may well give England boss Roy Hodgson plenty to ponder, and Laudrup added: "He is good in possession and good at making runs from midfield.
"I think he can also be the more dynamic midfielder but in these two games against Manchester City and Newcastle we have seen it suits him well."