The pan-European STOXX 600 index was flat in percentage terms, while Britain's FTSE 100 index advanced 0.2 percent and Germany's DAX declined 0.2 percent.
Spanish banks helped the IBEX shake off an early fall to gain 0.2 percent, after Santander said it would buy struggling peer Banco Popular and carry out a capital increase of around 7 billion euros ($7.9 billion).
Shares in Santander reversed course to trade 0.3 percent higher, while Banco Popular's shares were suspended. Peers BBVA and Caixabank also advanced.
Covestro dropped nearly 5 percent after Bayer cut its stake further in the plastics maker to 44.8 percent from 53.3 percent.
On the positive side, shares in utilities E.ON and RWE rose 4.7 percent and 3.8 percent, respectively, after Germany's highest court ruled that a nuclear tax is illegal.