The Welsh boss was confident that the deal for the versatile Cameroon international would be completed ahead of tonight's 23:00BST transfer deadline.
"He is en route as we speak," Hughes told a press conference. "Hopefully we will get him in to a medical quite quickly."
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"So once we get through the medical hopefully we will be able to conclude the deal very quickly. He is another player that can play in a couple of positions. I like that flexibility in players. He is a good age, and we have paid a good price for him."
The 26-year-old began his career as a defensive midfielder at Rennes, before earning a move to Marseille, where he was played at centre-back under manager Didier Deschamps with great success as Les Phoceens won Ligue 1 in 2010.
Rangers' move for M’Bia is likely to end the club’s interest in Michael Dawson, who is set to remain at Tottenham after Younes Kaboul sustained a knee injury.
Hughes was also confident of agreeing a season-long loan deal with the French club for Joey Barton, who incurred a 12 game ban in the final match of the 2011-12 Premier League season and is surplus to requirements at Loftus Road following the arrival of Esteban Granero from Real Madrid.
The French transfer window shuts on Tuesday, but Hughes hoped for a quick resolution, commenting: "I would have thought it would be concluded quite quickly. I would be surprised if it wasn't."