Barton reveals French death threat
The Englishman, 32, has created headlines throughout his career, including for serving a prison sentence in 2008 for common assault and affray.
Barton joined Marseille in August 2012, while still serving a 12-match ban for his sending off on the final day of the 2011-12 Premier League season while playing for QPR, and a subsequent altercation with City players Sergio Aguero and Vincent Kompany.
And he revealed on Wednesday that he had received a letter disapproving of his presence in Ligue 1, posting an image of what he labelled as 'fan mail' on his official Twitter page.
"A little friendly advice: as soon as you finish your season in your current club, I advice you to leave France immediatly," the error-strewn letter read.
"In fact, if you're not left France before June 1st, I will come to you specially Marseille smash your head shots baseball bat. And then I will finish and you'll die a knife open mouth once emptied your blood b******.
"Do you understand? You have until June 1st to leave France and return to your country mother*******."
Barton took the letter in good spirits, posting on Twitter: "Not sure what's more offensive, the grammar or the intent?"
Oddly, the writer chose to include their name and address on the letter.
Found some old 'fan mail'. Amazing what some people consider 'A little friendly advice' these days...? pic.twitter.com/MheWN8xvaW
— Joseph Barton (@Joey7Barton) December 10, 2014