LONDON, March 20 (Reuters) - European equity markets were seen opening slightly lower on Tuesday, continuing to consolidate the previous week's strong rally to eight-month highs and looking to U.S. economic data for a fresh catalyst. Financial spreadbetters expected Britain's FTSE 100 to open down seven to 13 points, or as much as 0.2 percent, Germany's DAX to ease eight to nine points, or around 0.1 percent, and France's CAC-40 to open six points, or 0.2 percent lower. The FTSE Eurofirst 300 closed down 0.1 percent at 1,105.61 points on Monday, snapping a four-session winning streak that took it to an eight-month intra-day high of 1,109.18 on Friday. With investors favouring European companies that are exposed to U.S.