According to this Wikipedia page about iron mines in France (in french), most of the iron at the iron age was collected in Lorraine (close to Germany/Luxembourg/Belgium). read more
From the Iron Age to medieval times, iron was produced by the bloomery method in which iron ore and charcoal were placed (generally after a preliminary roasting of the ore) within a small furnace that may have been little more than a hollow in the ground, especially in pre-Roman times. read more
In other regions of Europe the Iron Age began in the 8th century BC in Central Europe and the 6th century BC in Northern Europe. The Near Eastern Iron Age is divided into two subsections, Iron I and Iron II. Iron I (1200–1000 BC) illustrates both continuity and discontinuity with the previous Late Bronze Age. read more