Why France balked

It turns out that the French were planning to announce that they were only sending a token force last night. But then the UN—fearful of the "devastating effect" this would have on other potential contributors—secured a postponement of the announcement. (All the quotes here are from this Le Monde article, which a kindly Frenchman has translated for us.) The shift in France's position is...

...motivated, according to a senior military official, by "the trauma of Bosnia" and "fears of retaliation from Syria or Iran" - two regimes which support Hezbollah and against which France is leading diplomatic battles." 

To an extent, the French position is understandable. The mission won't be under Chapter 7, its purpose is fuzzy, and the Lebanese army isn't planning to disarm Hezbollah. That means either the French will have to perform this task—which won't be easy—or there's a good chance that hostilities between the IDF and Hezbollah will resume, leaving the French army "having nothing but hits to take," as a military source put it to Le Monde. 

Today, after a begging call from Kofi Annan, Jacques Chirac announced that France will dispatch 200 more troops to Lebanon. But France won't decide on whether to deploy in large numbers until the mission, the terms of engagement, and the proposed composition of the force have been clarified. That creates a classic chicken and egg situation because—as a UN civil servant told Le Monde—"European countries and the Muslim countries, everyone is waiting for France."