That is true in France, although I think in Germany a lot go right out to the countryside such as Berlin.
Berlin is very much the exception rather than the rule. And has a lot to do with the fact that the metro area's population was (marginally) declining throughout most of the second half of the 20th century. And with a certain wall. that kept Berlin's western and northwestern hinterland from fulfilling its suburban destiny (suburban development in the area had already begun in 1945. Since 1990, these areas have been growing like no tomorrow.)
And with the fact that East Berlin's big 70s and 80s mushrooming suburbs were built on heathland unexplically included in the city boundary back when all of Berlin's then many suburbs were consolidated into the city back in 1920.
There are vast commuterland belts around Frankfurt and Munich and Stuttgart. It's sort of hard to tell where they end because zoning laws - and rich soils, actually. And some other factors as well - have ensured the survival of quite extensive swathes of farmland well inside them (there's farmland between Offenbach and Sachsenhausen!). And Frankfurt's and to a lesser extent Stuttgart's have gobbled up several older smaller central cities.