Euro 96 Qualifiers - France had 5W and 5D during qualifying. Zidane featured in 4 of those 5 wins and 2 of those 5 draws. His greatest contribution was probably in the away game vs Romania (a team which ended up winning the group), wherein he assisted the opening goal and scored the 3rd one (great finish), to put the match to bed. He also scored and assisted in the 10-0 drubbing of Azerbaijan. Note that before Zidane started playing regularly for France in the qualifiers, they had 7 points after 5 games and were joint third alongside Poland, behind Romania and Israel in their qualification group.
Euro 00 Qualifiers - I have shared this earlier as well on this forum (so I will just copy paste here), but I do think that this tournament's qualifying campaign surely helps underline the Zidane dependency claim for the French NT of that era (in terms of his presence).
France played 10 games in this qualifying campaign and Zidane was unavailable for 4 out of these 10 games, during the middle of the campaign, due to a knee injury which required him to undergo surgery. In the 6 games that Zidane played in during that qualifying campaign (3 before injury and 3 after injury), France only dropped 4/18 points, with Zidane having 1 Goal, 1 Assist and 3 Pre-Assists among the 10 goals scored by France in these games. In the 4 games that he missed, France dropped 5/12 points (scoring 5 goals). This inspite of the fact that 3 of those 4 games which Zidane missed were home games for France. As you can see, Zidane did again score during this qualifying campaign (2nd goal in 3-2 away victory vs Armenia) and France were in danger of not qualifying after losing their way and falling to 3rd place in the group, post his injury (source -
http://www.theguardian.com/football/1999/jun/07/newsstory.sport4).
Euro 04 Qualifiers - The French team were in amazing form, and although Zidane did score 3 goals (2 vs Malta yes but also the winner vs Israel) and I believe also had 3 assists, I think it was his overall play that was important for the team more so than his direct contributions to goals. He ended up featuring in 7 of the 8 qualifying games while France ended up winning all 8 games.
WC 06 Qualifiers - In case of this qualification campaign, while much has been made of his and Makelele/Thuram's presence in contributing to the French team qualifying for the WC, post these players' return to playing, Zidane also did have an important goal to contribute. He scored the opening goal in the 4-0 win over Cyprus which was a must win game in which the French had to score as many goals as possible (since if Switzerland were to beat Ireland then France needed to win by 4 more goals to qualify, source -
http://www.espnfc.com/story/345459/goalshy-france-need-cyprus-strikes).
So in his own way, one can see that Zidane too was important for the French team when it came to them qualifying for major international tournaments. Overall source for Zidane goals and international appearances -
http://www.rsssf.com/miscellaneous/zidane-intl.html