It is however difficult to position people within the PS, because their statements and programmes follow internal tactical goals rather than political strategic positioning.

So, what does the PS stand for on economic and social issues apart from promoting the various factional leaders?

A vivid image of what should exist acts as a surrogate for reality. Pursuit of the image then prevents pursuit of the reality -- John K. Galbraith

Well, I would say it's the party that takes sustainability most seriously. They are dead against a runaway debt (maybe sometime too much so -it does seem the right time for a major infrastructure program in many countries, and France may be one of them), and have the most believable environment program.
They are also the most clearly pro-European party around. Whether you count that as social and economic I don't know, but nowadays I don't have much belief in aiming such policies purely at the country level.
They stand for laicity in a big way, despite the excessive religiosity of their leader. At least he keeps it reasonably private.
They are in favour of a union equal in rights to marriage for homosexuals (not enough in my view. It should be called the same for everone. Call it spirograph if you want, but make it the same for all).
They are, in general, for long term solutions. Sustainability is quite the mantra there.

And they are dead against mixing the roles in the separation of powers as we see daily at the moment.

Now, it may just be tactical on the part of Bayrou (how would I know), but I am pretty sure most militants are sincere in those positions. And it's clearly more of a militants' party than a leaders' party -actually leaders may be an overstatement in its use of plural.

Earth provides enough to satisfy every man's need, but not every man's greed. Gandhi