To simplify the expression, we first distribute the negative sign in front of the parentheses:

2,3m + 4,3 - 7,1 - 9,2n - 4,5 - 2,3 + 1,3n - 5,7

Next, we combine like terms:

2,3m - 7,1 - 4,5 - 2,3 + 1,3n - 5,7 + 4,3 - 9,2n

Now combine:

2,3m + 1,3n + (4,3 - 9,2n) - (7,1 + 4,5) - (2,3 + 5,7)

Subtract within parentheses:

2,3m + 1,3n - 4,9n - 11,6 - 7,1 - 5,7

Combine like terms again:

2,3m - 3,6n - 23,4

Therefore, the simplified expression is 2,3m - 3,6n - 23,4.