According to Julian Jackson in The Fall of France: The Nazi Invasion of 1940, during meetings of the Anglo-French Supreme War Council in 1939/40 during the "Phoney War", France was much more eager to launch an offensive war, as seen in their incursion into the Saar in the early days of the war, while the British held back.

Even British measures which were suggested, such as offensive bombing of industry in the Ruhr, were rejected by France which feared that retaliation against Britain and France would follow - and even in November 1939 there was talk of a German invasion of Belgium.

Operation Royal Marine (a plan to float mines up the Rhine) was again rejected for fear of German reprisals on France and Britain. By the evacuation of Norway in April 1940 the plan to bomb the Ruhr in a German invasion of Belgium was reprised.

Broadly speaking, the French knew the German tactics but were unprepared for them; as General Gamelin put it as soon as the Germans broke through at Sedan they realised their "inferiority of numbers, inferiority of equipment, inferiority of method". The French generals felt (probably rightly) that their best time to strike was when they launched their incursion into the Saar in the earliest days of the war while German troops were tied up in Poland. By late 1939 and early 1940 the risk of reprisal was too great to consider an all-out offensive on the Siegfried Line.

So the French Army expected that it would never have to face the blitzkreig as it would preempt it through offensive measures, but held back enough due to British reluctance to commit resources to such an offensive. I don't think there's anything to suggest they expected a trench war like in 1914 - they seemed to know that if the Germans broke through Belgium then due to their lack of strategic reserve they would be in serious trouble - hence their desire not to provoke Germany into invading Belgium.