Ok, time to look at the facts and numbers.
Fortifications: At the end of 1941 almost exclusively field fortifications only, with only fortified areas being the heavy coastal battery positions built to support Seelöwe, submarine pens and the Channel Islands.
Occupation forces: A large number of second-rate troops, static divisions tasked to protect the coast against commando operations. Formations raised during 1942 were really weak or refitting after being rendered combat ineffective in the Eastern Front. The static coastal divisions had a real zoo of artillery, with one third-of their artillery park of c. 1200 guns being captured foreign pieces with limited ammunition supplies and a logistical nightmare for prolonged combat.
The infantry regiments received modern German weapons to replace their WW-1 era equipment and captured small arms in 1942. In general the divisions in France were made up from recruits, recovering veterans and older reservists. The divisions trained new recruits and allowed recovering veterans to rest and refit before being sent back East. In addition there were Ersatz divisions, reserve units that were mostly used for training recruits.
Note that the limited supplies meant that the artillery units had no reserve to practice. There was no coordinated system for controlling the fire of the coastal artillery batteries, as Kriegsmarine and Heer had conflicting views on how to employ them.
Germans used France as a main training and refitting area for their new formations. Between February and September they created the 19th and 20th Welles, with 4 new divisions established and immediately sent to Eastern Front in March 1942, and 3 standard and 5 static divisions created in September.
Size of garrison during 1942, as divisions came and went:
Jan-March: 29 Inf (most of them static), April-June 31 Inf divisions, 3 motorized or panzer divisions (resting and refitting.)
July-September, 30 infantry divisions, 7 motorized or panzer divisions. (resting and refitting.)
October-December: c. 45 divisions, 10 of which went to occupy Vichy areas, 10 motorized or Panzer divisions, out of which one panzer and three SS panzer divisions went to occupy Vichy areas. (all are still resting and refitting and due to leave back to East as soon as they have recovered.)
Do note that the actual number of divisions is deceptive, as many divisions sent back from the Eastern Front in OTL were shattered formations that required extensive refit and rest to restore their operational capacities.
So during 1942 there was a buildup from 29 to 35 infantry divisions, and from no panzer reserves to 6-7 armored and motorized units resting and refitting in France.
The Germans started 1942 with 25 divisions in the West, 20 of which were static coastal divisions, with 3 more divisions due to head out to the Eastern Front.
After the Dieppe Raid, they really started to reinforce their garrisons by sending battle-worn divisions like the 7th Panzer to the West for rest and refit for prolonged periods of time.
Now, compare this to 1943:
German strategy:
The German commander, von Rundstedt, wanted to create a mobile reserve, but since he did not have one at the beginning of 1942, he was forced to try to defeat the Allied landing at the coast.
Until mid-November 1943, when Panzergruppe West was formed, the only permanently deployed armoured unit in France was the 100th Panzer Brigade, using captured French tanks and obsolete German panzers.
In 1942 von Rundstedt believed that it would be impossible to maintain enough good units in reserve to launch the counterattack he believed necessary to drive the Allies back into the sea, and that the bulk of his forces could only defend the coastline as a static garrison formation. This state of affairs was not remedied until late 1943, when Hitler issued Directive Number 51.
Source: The Atlantic Wall - History and Guide, by J.E. Kaufmann, H.W. Kaufmann,
Jankovic-Potocnik, A. & Tonic, Vladimir