Translation:These shoes are soon available at the shoe department.
I would say either but I would definitely say 'avalaible soon' rather than 'soon available' and would only use 'at' if the Shoe Department were a franchise, I'd say 'in' otherewise.
As far as I know, near future events can be expressed in the present tense in English, French and, apparently, Dutch.
Otherwise stated, in English, ALL non-posessive adjectives are singular, unlike in many other European languages where they must agree in gender and number with the noun they describe. So that is why we have words like toothbrush, hairbrush, footstool, etc. (not teethbrush, hairbrush and feetstool.) That is why we buy shoes IN the shoe department, not the shoes department. We must also say in, just as we say someone is cooking IN the kitchen, not someone is cooking at the kitchen.