This paper provides new insights into how wages and employment adjust to a minimum wage policy along different wage and skill groups. For this, we exploit a quasi-experimental setting in the 1990s, where a German industry introduced a minimum wage at an extraordinary high level during an economic downturn with falling revenues. We find positive wage spillovers to medium-skilled workers with wages just above the minimum wage. More striking, we also find negative wage effects for high-skilled workers situated higher up in the wage distribution, followed by reduced returns to skills and skill supply in the industry. We explain these adjustments, both theoretically and empirically, with a substitution-scale model that predicts negative spillovers whenever labour demand shifts from low- to more skilled workers (substitution effect) are overcompensated by an overall decline in labour demand (scale effect).