参见下面的片段。
首先，您的input字段超出了col的width。因此将max-width:100%设置为它们
第二，.btn有inline-block样式，使用display:block代替
如果对你有用，请告诉我

input { 
  max-width:100%
}
.form-group .btn {
	display:block;
}

<link href="https://netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet"/>
<script src="https://netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<form class="form-inline">

  <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label">De</label>
      <input type="email" value='' id="name" placeholder="Ime">
  </div>
  <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label">A</label>
      <input type="email" value='' id="name" placeholder="Ime">
  </div>
  <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label">Départ</label>
      <input type="email" value='' id="name" placeholder="Ime">
  </div>

  <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label">Retour</label>
      <input type="email" value='' id="name" placeholder="Ime">
  </div>

  <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label"></label>
      <button type="submit" class="btn btn-default">recherche</button>
  </div>

</form>

在要对齐的按钮顶部添加一个带有 的空标签，如下所示

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">



<form class="form-inline">
    
      <div class="form-group col-xs-2 col-md-2">
          <label for="name" class="control-label">De</label>
          <input type="email" value='' id="name" placeholder="Ime">
      </div>
      <div class="form-group col-xs-2 col-md-2">
          <label for="name" class="control-label">A</label>
          <input type="email" value='' id="name" placeholder="Ime">
      </div>
      <div class="form-group col-xs-2 col-md-2">
          <label for="name" class="control-label">Départ</label>
          <input type="email" value='' id="name" placeholder="Ime">
      </div>
    
      <div class="form-group col-xs-2 col-md-2">
          <label for="name" class="control-label">Retour</label>
          <input type="email" value='' id="name" placeholder="Ime">
      </div>
    
      <div class="form-group col-xs-2 col-md-2">
          <label for="name" class="control-label">&nbsp;</label>
          <button type="submit" class="btn btn-default">recherche</button>
      </div>
    
    </form>

您的按钮不应该在表单组中，而且这也不是标记内联表单的常用方法（使用XML）。请看这个例子，为了简洁起见，我使用了你的一些字段：

<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">

<form class="form-inline">

  <div class="form-group">
      <label for="name" class="control-label">De</label>
      <input type="email" value='' id="name" placeholder="Ime">
  </div>
  
  <div class="form-group">
      <label for="name" class="control-label">A</label>
      <input type="email" value='' id="name" placeholder="Ime">
  </div>

 <button type="submit" class="btn btn-default">recherche</button>

</form>

添加标签后，像这样

<script src="https://code.jquery.com/jquery-2.2.4.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<form class="form-inline">
    <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label">De</label><br />
      <input type="email" value='' id="name1" placeholder="Ime">
    </div>
    <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label">A</label><br />
      <input type="email" value='' id="name2" placeholder="Ime">
    </div>
    <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label">Départ</label><br />
      <input type="email" value='' id="name3" placeholder="Ime">
    </div>
    <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label">Retour</label><br />
      <input type="email" value='' id="name4" placeholder="Ime">
    </div>

    <div class="form-group col-xs-2 col-md-2">
      <label for="name" class="control-label"></label><br />
      <button type="submit" class="btn btn-default">recherche</button>
    </div>
</form>

为窗体标签和控件标签类添加不可分割的空格对我很有效

<label for="name" class="form-label control-label">&nbsp;</label>