A Black realtor and his clients were treated like first-rate criminals during a house showing in Michigan, when police showed up with the cavalry and guns drawn on a mistaken 911 call.

Eric Brown was giving a tour last week to Roy Thorne and his 15-year-old son, when all of a sudden ... they say they found themselves surrounded by a number of police cruisers outside, with some of the officers pointing their weapons at them and demanding they step out.

All three of them did what the cops asked, and they were all cuffed and briefly detained -- this while the cops asked them questions. Apparently, a concerned neighbor called in to report a break-in ... as it seems there was one that had happened the week prior, with the suspect's car at the time having a similar look to the one Eric was driving on this day.

As a result, the City of Wyoming Police Dept. came swarming in. After sorting out what was what -- with Eric explaining he was a realtor and was just showing off the place -- the police finally realized they were in the wrong ... and released everyone without further incident.

Everyone seemed to be on good terms as things wrapped up -- with the cops apologizing for the inconvenience -- but Eric and co. are still angered over it ... now claiming racial profiling.