Wennink, 66, has overseen a period of blistering growth for ASML since being elevated to CEO from finance chief in 2013, becoming Europe's largest technology company with market capitalisation of 250 billion euros ($274 billion) as its stock rose by more than 1,000%.
While Wennink held top jobs at ASML the company came to dominate the lithography market, the segment of the chipmaking industry that uses light to help print chip circuitry, leaving behind Japanese rivals Nikon (7731.T) and Canon (7751.T).
Fouquet, a French national who has been with ASML for 15 years, has previously overseen its extreme ultraviolet (EUV) product lines, which now account for about half of the company's sales. EUV technology was developed and commercialised by ASML, and is used by only a handful of manufacturers to make advanced chips.
EUV machines are the size of a school bus and cost $200 million each.
Customers include Taiwan's TSMC (2330.TW), Samsung (005930.KS), Intel (INTC.O) and memory chip manufacturers Micron (MU.O) and SK Hynix (000660.KS).
The last years of Wennink's term have seen the U.S. government pressuring the Dutch government to restrict ASML from selling EUV products in China - its third largest market after Taiwan and South Korea.
"There was a clear intent to prevent basically very advanced chip technology in China," Fouquet said on a call, adding that without EUV it was extremely difficult to go beyond a certain technology.
However he said is less clear whether additional restrictions on older technology will be effective or what their goal is.
"It's fully up to the U.S. to decide what they believe is right or not for themselves," he said.
Fouquet also confirmed that ASML is on track to ship the first pilot machine of its next product line, "High NA" EUV, by the end of this year. Intel has said it is the buyer.
"It's being packed as we speak, in fact, some pieces of it have already been shipped," he said.
Fouquet worked at U.S. chip equipment companies Applied Materials (AMAT.O) and KLA (KLAC.O) before joining ASML in 2008.
"Christophe's career is a clear example of natural evolution throughout the company," Wennink said. "He knows all our customers, suppliers, people, shareholders."
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