Yesterday was the official beginning of France’s presidential election campaign, with less than two weeks to the first round of voting on 22 April.

The candidates, of course, have been campaigning solidly for several weeks already, but this is the point at which official rules for campaign broadcasts and public postering come into effect — the carefully regulated noticeboards where all candidates have their posters displayed are a feature of French towns.

Most attention is still focused on the two front-runners: Nicolas Sarkozy of the centre-right UMP, and the Socialist Party’s Segolene Royal. Since the beginning of the year, opinion polls have consistently shown that Sarkozy will win if they face each other in the second round run-off; the margin has been very stable at around 54%-46% (Wikipedia maintains a record of the poll results).

Sarkozy’s capacity to self-destruct should not be disregarded — a recent ministerial colleague, Azouz Begag, has already claimed that Sarkozy threatened to “smash his face in” — but at this stage he appears to have Royal’s measure.

The contest for second place, however, is of critical importance: recent polls show Francois Bayrou, candidate of the liberal-centrist UDF, within a few percentage points of beating Royal and therefore advancing to the second round against Sarkozy. Sunday’s daily survey by Ipsos put the gap at only 3% — 22.5% to 19.5%. The far-Right’s Jean-Marie Le Pen is safe in fourth place, with support hovering around 14%. A further eight candidates make up the field, none of them with more than about 5%.

We know that it’s possible for the Socialist candidate to run third: it happened last time, when Le Pen just edged ahead of Lionel Jospin, only to be crushed by Jacques Chirac in the second round. But if Bayrou makes it into the second round, most of the Left’s vote would rally to him, making him the likely winner.

The big question for the next fortnight is whether tactical voting on the Left will prompt a switch to Bayrou in the first round. If enough people decide that Royal cannot win, and that beating Sarkozy is the top priority, then it’s just possible that Bayrou could pull off an unlikely victory.