Looking at the situation at the turn of the year (i.e., before this new transaction), the total balance sheet value of the properties was €7.6 billion and debt was €3.4 billion. Thus, the net value for shareholders based on balance sheet values would be €4.2 billion, but the markets do not believe in the balance sheet values; instead, the company’s market cap is only €2.3 billion. So, when calculating it this way, debt + market cap = approx. €5.7 billion. Can’t it be concluded from this that the market thinks there is roughly 25% “air” in the balance sheet values, but the value of the properties is still €2.3 billion higher than the debt? 
A view based on which the “real value” of the properties would be lower than the debt would require that the balance sheet values have over 50% “air”.