Paris Saint-Germain pretty much broke the football market back in the summer of 2017.

The Qatari-owned club wanted to elevate the Ligue 1 champions to the dizzying heights of Real Madrid and Barcelona.

How did the try and do it? By splashing nearly €400m on Neymar and Kylian Mbappe.

Neymar arrived from Barcelona that summer for €222m, while Mbappe signed initially on-loan from Monaco, before costing the Parisian side a cool €180m.

The duo helped guide PSG to the title and have started this season in stunning fashion.

Neymar has 14 goals in 16 matches, while Mbappe has 13 in 14 - PSG have won every Ligue 1 game so far as well.

The pair appear to get on very well on and off the pitch, as seen in their celebrations for Neymar's goal in the 2-1 win against Liverpool on Wednesday.

Nevertheless, there are constant rumblings about Neymar being unhappy in Paris and some interesting inside information has been made public courtesy of journalist Duncan Castles.

His report about the Brazilian's desire to leave France contains an interesting quote from an inside source about his relationship with Mbappe.

"Neymar left Barca because he didn't want to spend any more time in Messi's shadow," the source claimed, per Daily Record.

"But he actually liked Messi. Now he is in Mbappe's shadow at PSG, and he doesn't like Mbappe."

The report states that Neymar is not happy with the fact that Mbappe appears to be the 'poster-boy' of Thomas Tuchel's side.

Castles notes that against Liverpool, PSG's attack was built around Mbappe, not Neymar.

The Brazilian does have a clause in his contract that would see him sold if a team were to bid €215m for him in the summer of 2020.

However, the Brazilian will be 28 by the time the clause becomes active and it's unlikely a team would be willing to invest that kind of money.