The 25-year-old has signed an initial 18-month contract with an option to extend with the Championship side.
Boro manager Tony Mowbray said: “Maximilian was very keen to come here and test himself in English football.
“It’s a challenge for him and his arrival will create additional competition for places in that area of the pitch.
“He is a real competitor and comfortable with the ball. The challenge for him is to acclimatise to the English game and then take any opportunity that comes his way.”