The teenage striker's equaliser denied Swansea boss Sousa a win over the club which sacked him just under a year ago.
Nathan Dyer had fired the Welsh side into the lead just before the hour mark, but German's close-range strike sent them back up the
M4 with a solitary point.
Rangers were given a glimpse of what might have been with Sousa's new side flying high in fifth.
The hosts, on the other hand, are on their sixth manager since his departure and are still glancing over their shoulder at the relegation zone.
Sousa spiced up the encounter further by criticising the style of play of Neil Warnock's teams, but he is unbeaten in three meetings with the current Rangers boss this season after a win and a draw against his old club Crystal Palace.
But it was the hosts who almost made a stunning start when Akos Buzsaky's snap-shot flew narrowly wide after just two minutes.
Tottenham loanee Adel Taarabt was his usual box of tricks and he mesmerised Swans left-back Ashley Richards before teeing up Peter Ramage whose low cross was blasted wide by Hogan Ephraim.
Rangers had a let-off in the 12th minute when Dyer ran onto Shefki Kuqi's flick-on and poked his shot wide of goalkeeper Carl Ikeme, only to find the inside of the post.
Taarabt had the ball in the Swansea net after 37 minutes when Kaspars Gorkss' deflected shot fell to him but he was well offside.
Guillem Bauza should have put Swansea ahead just before the break when Kuqi played him in in front of goal.
The Spaniard is good friends with Fernando Torres but the Liverpool star's finishing has clearly not rubbed off on him as he fired weakly at Ikeme.
But Bauza did have a hand in the goal after the break when his harmless-looking pass cannoned off the head of Rangers defender Matt Hill.
The ball fell into the path of diminutive winger Dyer, who calmly tucked it past Ikeme from 12 yards for his second goal of the season.
But Rangers dragged themselves level in the 75th minute when Swansea failed to deal with a corner, Rowan Vine drilled across goal and German was on hand to bundle the ball over the line.
Rangers thought they had a grabbed a late winner when Matt Connolly headed home but the defender was adjudged to be offside.