Well, it's very complicated... from the Beeb:
The Netherlands have won Group C and will play the Group D runners-up in the quarter-finals.
Romania will qualify for the quarter-finals if they beat the Netherlands, eliminating France and Italy.
If Romania fail to beat the Netherlands, the winner of France v Italy will go through.
If France and Italy draw, a point against the Netherlands would be enough to send Romania through. France must win to have any chance of qualifying.
If France and Italy share a score draw (1-1, 2-2, 3-3 etc), Italy will go through if Romania lose (by any score). In this scenario, Italy, Romania and France will be level on two points each but Italy would have scored more goals in games between the 3 teams.
Romania will finish bottom of the group if they lose and France and Italy draw 2-2, 3-3 or 4-4. France will finish bottom if they draw 1-1 unless Romania lose 3-0 or by a four-goal margin.
If France and Italy draw 0-0, Romania can lose by one goal, two goals or by a three-goal margin other than 3-0 but still qualify. In this scenario, Italy and Romania would have identical head-to-head records, but Romania would have better goal difference in ALL group matches or, in the case of the three-goal defeats, goals scored. France would finish bottom, having scored fewer goals head-to-head v Italy and Romania.
If Romania lose 3-0 to the Dutch, Italy would qualify with a 0-0 draw against France because of their superior coefficient points. France would finish bottom as they would have scored fewer goals head-to-head v Italy and Romania.
If Romania lose by four goals or more and the other game ends 0-0, Italy would proceed with a better overall goal difference than Romania. France would finish bottom as they would have scored fewer goals head-to-head v Italy and Romania.
If France and Italy draw AND Romania avoid defeat, then Romania go through. France and Italy will have identical records and a unprecedented penalty shoot-out will decide who finishes third and fourth.