European stocks opened lower Friday as investors adopted a defensive stance ahead of key U.S. employment data amid a pullback in the dollar and increasing questions over the recent "Trump rally."

The region-wide Stoxx 600 index, the broadest measure of European shares, slipped 0.2% by 08:30 GMT as benchmark indices drifted modestly lower across the board. Britain's FTSE 100 was little changed immediately after the bell, while the DAX in German and the CAC 40 in Paris notched modest declines.

Shares in Sanofi  (SNY - Get Report) were an early mover of note after the French pharma group said it would appeal an injunction from a U.S. court that would ban the sale of its key Praluent cholesterol drug on the grounds of patent infringement. 

"It is our longstanding position that Amgen's patent claims are invalid and that the best interests of patients will be greatly disserved by an injunction preventing access to Praluent," the company said in a statement.

Shares fell 2.6% in early Paris trading, the biggest single-day decline in at least six months, to change hands at €76.15 each by 08:30 GMT.

Overnight in Asia, regional stocks continued to take advantage of the dollar's decline, rising briefly to a 4-week high before paring gains into the close of trading. The MSCI Asia ex-Japan Index was quoted 0.02% lower at 08:30 GMT while the Nikkei 225 fell for the second consecutive session, closing 0.3% lower at 19,454.33 but still notching a weekly advance of 1.8%.

Automakers led the Japanese benchmark lower, however, with Toyota Motor (TM - Get Report) falling as much as 3% in early trading following the latest Twitter attack from President elect Donald Trump, who criticised the group's plans to manufacture its Corolla model in Mexico for sale in the United States. Honda Motor (HMC - Get Report) and Nissan were caught in the downdraft, which elicited a response from Japan's chief cabinet secretary Yoshihide Suga, who called the world's biggest carmaker an "important corporate citizen". Its shares recovered as the session continued, ending down 1.69%.

The dollar continued its poor run of form in overnight trading, touching a three-week low of 101.30 before rebounding somewhat to around 101.61 in early European dealing. Bond markets traced the dollar moves - although some analysts suggest they actually led them - helping lower benchmark 10-year Treasury yields to a one-month low of 2.34%.

Investor focus will now switch to Friday's employment report from the U.S. Labor Department, set for release at 13:30 GMT, which is expected to show that the world's biggest economy added 178,000 new jobs in the month of December. However, a largely disappointing reading of private-sector hiring, published Thursday by ADP, has some investors bracing for a much more tepid reading.

The Dow Jones Industrial Average's shot at 20,000 looks increasingly ambitious as disappointing holiday sales and fresh store closure announcements from retailers soured broader market sentiment Thursday and dragged U.S. equity benchmarks lower.

The Dow slid 0.21% to 19,899, the S&P 500 was down 0.08%, and the Nasdaq was up 0.20%.

Early indications from U.S. futures prices suggest a third day of declines for U.S. stocks, with the Dow falling 7 points, the S&P 500 1 point and the Nasdaq opening with little change.