OK, so the thing in your picture is a custom variation on a DIN 41529 loudspeaker connector.

You have a chassis-mount male connector, in the picture.

The mating connector, as far as pin layout goes is one of these:

https://www.amazon.com/10Pcs-Female-Loudspeaker-Connectors-Speaker/dp/B07SL64NMH/

The original one for your appliance had non-standard plastic bodywork.

The ones I've listed in the Amazon link are definitely correct as far as the metal contacts go, and might or might not fit in the recess in the plastic of the socket.

If they don't, your only real option is to MacGuyver the plastics to fit as the connector on your sofa is a customised version of the standard part.

So that's one piece of the puzzle.

As for what voltage / current / polarity the original power supply was (which you'd need to find a matching replacement for, and then fit the above mentioned connector), it's not possible to tell from just the picture.

If I had to guess (and it is a guess), 12v DC and the larger of the two contacts in the plug is negative, the smaller positive. As for current, I can't see it being more than five amps. But all of this paragraph is a guess, with perhaps a 50-50 chance of being right or wrong.