The difference with the American Veep is that s/he is elected on a ticket with the pres. As you know, the Veep exercises more or less power. Cheney is very much on the more side.

In fact, there is no equivalent in the American constitution to the French PM. Or imagine that, when the president appoints the Sec of State, of Defense, the Attorney General, etc, he also appoints a coordinator of executive activity. Sounds stupid because the president is in fact (with more or less help from the Veep) that coordinator.

My personal view is that the French system on this point is full of BS. The PM is there to support a polite fiction, which is that the president is above the fray and doesn't mind the shop. The PM's work is real, but his main function is to make it look as if things are getting done, and to take the rap if not. He is often a lightning conductor for the president -- he gets fired when things go wrong, the president sails on regardless.

That leads to an answer about whether it's a vote of confidence to be appointed PM. Yes. But it's a very risky position. Ideally, a presidential candidate would want to keep away from it. (So why did Villepin take it on? No doubt because he has a high opinion of his ability to make France fall in love with him [his actual words on this seem to have been more buccaneering...])

The US VP analogy is possible but potentially confusing since for it to be more accurate you'd have to imagine the VP as representing the senate majority (actually it would have to be the congressional majority) not necessarily the president's party or choice. France had many years of "cohabitation" governments in which the president was from the right or left and the PM was from the opposite party which was the ruling majority in parliament. Presidential terms in France were for 7 years up until 2001 when they were reduced to 5 years. This was plenty of time for the electorate to decide they had had enough and change the parliamentary majority thus forcing a cohabitation government.

The brookings institute's web site has an article by Olivier Duhamel, Professor of Constitutional Law and Political Science at Sciences Po Paris, that discusses the French electoral system and provides this graph of the 5th republic presidents and prime ministers illustrating the cohabitation of red and blue:

The recent change in the presidential mandate from 7 to 5 years has not yet been tested in a cohabitation situation, but I don't expect it to be different.

With the presidential and parliamentary terms now in lockstep with each other, I don't think the likelyhood of cohabitation in the future is very high...

guaranteed to evoke a violent reaction from police is to challenge their right to "define the situation." --- David Graeber citing Marc Cooper

I agree Jospin's five-year PMship significantly moved the cursor towards PM and ministerial autonomy. I'd submit that Chirac's last four years, particularly with non-entity PM Raffarin, have ignored that movement.

In future I'd expect the trend to be towards more actual power to the PM, but there's no guarantee of this. Seeing the autocratic tendencies of a Villepin, for example, makes me wonder what kind of PM he would appoint and what autonomy he would give that person if he were PRF. He would have the constitution on his side if he chose to act like a monarch (which many, don't forget, considered Mitterand did in his time...)

I would like to see changes in the constitution linking the PM more directly to the parliamentary majority, as happens by convention during cohabitation periods.

Can you give an example of a scenario in which the President and the parliament have differed on policy and the PM has not acted in the interest of the President but of the National Assembly instead, trumping the President's power?  How would this work?  Why would the PM not represent the President's agenda?  Who has veto power, does the PM cast deciding votes, or is it mostly a position of influence and lobbying (when pres. has majority) and diplomacy (during "cohabitation")?

Also, I am confused again.  Upthread, afew states that the President chooses the PM, not the parliament:

In France, like in the US, the head of state is an elected president who does have a lot of political power. That, among others, of appointing the executive.
...
(and)
the French pres chooses a PM who draws up a list of ministers for approval (in fact the pres does most of the choosing).

and you say:

the executive power is in fact vested with the PM, chosen by the National Assembly.

Even during "cohabitation" the President still picks the PM, just from a different party.  Who has the final say on policies?  The President or the PM?  

Those who can make you believe absurdities can make you commit atrocities. -Voltaire