Suleiman Al-Sadi, from Bristol, said members of staff at a store in the city whistled and laughed at him while he was shopping for a sofa last Tuesday.
He said he was "shocked and horrified" when they made jokes about his "camp" appearance.
DFS said an investigation was under way and several staff had been suspended.
Mr Al-Sadi said "five sales guys" looked at him and started laughing when he walked into the shop at Cribbs Causeway.
He said one of them joked they "should probably take him to look around the beds".
"I was shocked, confused, horrified. A couple of them started whistling. I felt like I'd stepped back into the 1970s.
"They were trying to taunt me. It was making fun and jokes of my appearance. They didn't take me seriously."
Mr Al-Sadi complained to DFS. The company said it was "disappointed" to hear of the allegations and was "taking it extremely seriously".
A spokesman said: "We have apologised to the customer for any unintentional distress caused and remain in regular dialogue with him as we look into the issue further.
"Following the complaint, a formal investigation is under way and several employees have been suspended pending completion of the investigation.
"Should anyone be found to have breached our standards, further disciplinary action will be taken."

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And that is why he chose Manchester United striker Marcus Rashford ahead of Leicester midfielder Danny Drinkwater.
Hodgson, speaking before Thursday's final friendly against Portugal at Wembley, said his selection was "tilted towards an offensive approach".
He added: "It became a question of do I take the extra attacker or midfielder? That's how Rashford came about."
Hodgson's side begin their Group B campaign in France against Russia on 11 June, before meeting Wales on 16 June and Slovakia on 20 June.
Eighteen-year-old Rashford's rapid rise into the England squad, scoring on his debut against Australia last week, was described as "incredible for his age" by captain Wayne Rooney.
And Hodgson added: "Rashford's had that fantastic end to the season and it will be very interesting to see in a squad of 23 whether he can bring those qualities at a higher level."
Hodgson, 68, has been criticised for picking just three recognised central defenders but he is confident England will be solid in defence.
"We believe defending is very much a team job and we can't just rely on a back four and a goalkeeper," he said.
"We need great mobility and great running power to defend in that way. With this squad they've got the ability to give us that.
"Often in a tournament the players that get injured or suffer a lack of form are the guys at the cutting edge, the guys who make the difference or score the goals."
He added he was happy he had so many good players to put on the field.
"Systems win you nothing and football players win you games," he said. "If they perform anything like they're capable of we'll be a tough team to beat."
Who do you think should start at Euro 2016? Step into Roy Hodgson's shoes and pick your XI - and then share it with your friends using our brand new team selector.

Tozer, 26, spent 2015-16 at Yeovil, who he joined from Northampton.
The Plymouth-born player said: "It has been a bit of a whirlwind with the deal being sorted out so quickly, but I'm delighted to get the deal done and over the line."
Newport manager Warren Feeney said: "He has experience at this level which will be a great benefit for us."
Find all the latest football transfers on our dedicated page.
A number of employees at a DFS furniture store have been suspended over allegations they made fun at the appearance of a customer.
[NEXT_CONCEPT]
Manager Roy Hodgson says his final 23-man England squad for the European Championships is based on attack.
[NEXT_CONCEPT]
Defensive midfielder Ben Tozer has joined League Two's Newport County on a one-year deal.