Hart in der Sache, weich zum Menschen — hard on the matter, soft on the person. A common German rule for criticism. The SPD’s party school uses the variant Hart in der Sache, fair zu den Menschen, hard on the matter, fair to the people.
sachlich bleiben — to stay factual, to keep to the matter
sachliche Kritik — criticism of the matter
Kritisieren Sie immer die Verhaltensweisen — always criticize the behavior, never the traits, as a management guide for dental practices advises
The first motto is the German form of a principle from the Harvard negotiation method of Roger Fisher and William Ury, published in 1981 as Getting to Yes.