The former City loanee, who is expected to be back at the Ricoh Arena on Saturday with Burnley, played in a game which saw Christian Rausch put Germany ahead in the 37th minute.
Stuart Pearce, himself a former Coventry City player, made a change in goal at half-time and brought on Middlesbrough's Jason Steele for his debut in place of Scott Loach.
However, Steele did not have the best of debuts and was harshly sent off in the 58th minute, forcing Henri Lansbury to take over in goal.
Lansbury's first job was to pick the ball out of the net as Tosun scored the resulting penalty and condemed England to their first away defeat in five years.